THE 9th INTERNATIONAL CONFERENCEON HARD X-Ray PHOTOELECTRON SPECTROSCOPY

HAXPES
2022

May 31 - June 3, 2022
Himeji, Japan
Conference format : In-person + Online hybrid
Place : Arcrea HIMEJI (Himeji Convention Center)
Early bird registration deadline : February 28, 2022
Abstract deadline : December 10, 2021 (Oral presentation)
January 31, 2022 (Poster presentation)

Co-chairs :Eiji IKENAGA (Nagoya University)
Masaki OURA (RIKEN SPring-8 Center)
Akira SEKIYAMA (Osaka University)
Information and registration :http://rsc.riken.jp/haxpes2022/ Contact : haxpes2022@spring8.or.jp

Hosted by RIKEN SPring-8 Center & HAXPES2022 Organizing Committee

Supported bySponsored byJapan (UTC+9)

5/31 (Tue.)

9:00

6/1 (Wed.)

6/2 (Thu.)

1a1-1 : Invited (On-site)

2a1-1 : Invited (On-line)

Hidenori Fujiwara
Topic 1 : Atomic and Molecular Science

9:30
Topic 2 : Correlated and Magnetic Materials

10:00

1a1-2 : Oral (On-line)

Chair :
S. UedaAlexander X. Gray
1a1-3 : Oral (On-site)

11:00

Topic 5

: Energy Research and Industrial

1a2-1 : Invited (On-line)

Chair :

3a1-2 : Invited (On-line)

A. Gray

Kelvin Zhang

Lothar Weinhardt

Eric L. Shirley

Applications

Breakout session

2a1-5 : Invited (On-site)

Topic 6 : Techniques and Instrumentations

1a2-2 : Oral (On-site)

Chair :

Topic 7 : New Trends and Applications

Hsun-Yun Chang
1a2-3 : Oral (On-line)

K. Mimura

Akira Yasui

Trung-Phuc Vo
1a2-4 : Oral (On-site)

Closing

Dirk Hauschild

Concluding remarks by Wolfgang Drube

11:30

Next venue

12:00
Lunch session

12:30

Open discussion
&
Lunch

13:00

13:30

Company presentation

Chair :
S. Yasuno

14:00

1p1-1 : Invited (On-site)
Atsushi Hariki

14:30

1p1-2 : Oral (On-line)

Chair :

2p1-1 : Invited (On-line)

M. Taguchi

Stephen H. Southworth

J. Matthias Kahk
1p1-3 : Oral

15:00

2p1-2 : Oral (On-line)

Victor Kimberg
Coffee break

15:30

Minna Patanen
2p1-3 : Oral (On-site)

Chair :

Faris Gelmukhanov

M. Oura2p1-4 : Plenary (On-line)
Marc Simon

1p2-1 : Plenary (On-line)

16:00

Michael Sing
Chair :
1p2-2 : Oral (On-line)

16:30

17:00

(TBD)

2p2-1 : Oral (On-line)

Fredrik O.L. Johansson
1p2-4 : Oral (On-line)

Natalia M. Martin
2p2-2 : Oral (On-line)

Announcement
18:00

18:30

2p2-3 : Invited (On-line)

1p3-1 : Oral (On-line)

Sara Blomberg

J.-P. Rueff
1p3-2 : Oral (On-site)

2p2-4 : Oral (On-line)

Daisuke Takegami
1p3-3 : Oral (On-line)

Opening : Tetsuya Ishikawa

Chair :
E. Ikenaga

Pierre-Marie Deleuze
1p3-4 : Oral (On-line)

31n1-1 : Plenary (On-line)

Patrick Lömker
2p2-5 : Oral (On-line)
Eugenie Martinez
2p2-6 : Oral (On-line)

Sunil Wilfred DSouza
Memorial Talk

Gerd Schönhense

19:00

Andrew J. Naylor

Short break

17:30

Coffee break

Jan Minar
1p2-3 : Oral (On-line)

Curran Kalha
Registration

Dibya Phuyal

Charles Fadley & Yasutaka Takata

31n1-2 : Oral (On-line)
Andreas Lindblad
31n1-3 : Oral (On-line)

Chair :
W. Drube

Julius Hållstedt
19:30

31n1-4 : Invited (On-line)

Dinner & Poster session
Dinner session

Christoph Schlueter
20:00

31n1-5 : Oral (On-line)
Vladimir N. Strocov
31n1-6 : Oral (On-line)
Martina Müller

20:30

1n1-1 : Invited (On-site)
Marcus Bär

21:00

Dinner & Night session

1n1-2 : Oral (On-line)

Chair :
Y. Yamashita

Yoshiyuki Yamashita
2a1-4 : Oral (On-site)

Topic 4 : Theory

10:30

Bongjin Simon Mun
2a1-2 : Invited (On-site)

2a1-3 : Oral (On-site)

Short break

3a1-1 : Plenary (On-line)

Slavomir Nemsak

Shigenori Ueda

Munetaka Taguchi

Topic 3 : Functional Interfaces

6/3 (Fri.)

Chair :
R. Claessen

Austin Irish
1n1-3 : Oral (On-line)
Jay R. Paudel
21:30
IAB meeting

Chair :
T. -L. Lee

Organizing Committee
Co-Chairs:
Akira Sekiyama
Eiji Ikenaga
Masaki Oura

Osaka University, Japan
Nagoya University, JapanRIKEN SPring-8 Center, Japan

International Advisory Board and Program Committee :German Castro
Ralph Claessen
Wolfgang Drube
Mihaela Gorgoi
Alexander Gray
Eiji Ikenaga
Olof Karis
Tien-Lin Lee
Jan Minar
Martina Muller
Masaki Oura
Giancarlo Panaccione
Piero Pianetta
Anna RegoutzHåkan Rensmo
D.D. Sarma
Akira Sekiyama
Marc Simon
Elie Sondergaard
Shigemasa Suga
Amina Taleb-Ibrahimi
Liu Hao Tjeng
Ku-Ding Tsuei
Joseph Woicik
Jörg Zegenhagen

ESRF, France
Universitat Wurzburg, Germany
DESY, Germany
BESSY, Germany
Temple University, USA
Nagoya University, Japan
Uppsala University, Sweden
Diamond Light Source, UK
University of West Bohemia, Czech Republic
Konstanz University, Germany
RIKEN SPring-8 Center, Japan
Istututo Officina dei Materiali CNR, Italy
SLAC, USA
University College London, UK
Uppsala University, Sweden
Indian Institute of Science, India
Osaka University, Japan
Sorbonne Universite & CNRS, France
Laboratoire Surface du Verre et Interfaces (CNRS / Saint-Gobain), France
Osaka University, Japan
Synchrotron Soleil, France
Max Planck Institute for Chemical Physics of Solids, Germany
NSRRC, Taiwan
NIST, USA
Diamond Light Source, UK

Local Organizing Committee :Eiji Ikenaga
Masaki Oura
Akira Sekiyama
Hidenori Fujiwara
Satoru Hamamoto
Yasumasa Takagi
Akira Yasui
Satoshi Yasuno

Nagoya University, JapanRIKEN SPring-8 Center, Japan
Osaka University, Japan
Osaka University, JapanRIKEN SPring-8 Center, JapanJASRI, JapanJASRI, JapanJASRI, Japan

Program
Tuesday, 31 May, Hotel Monterey Himeji
17:00 - 17:45
17:45 - 18:00

Registration
Announcement

18:00 - 18:15

Opening, Tetsuya Ishikawa (RIKEN SPring-8 Center)

Chair: Wolfgang Drube
18:15 - 19:00

Plenary talkGerd Schönhense (Johannes Gutenberg University, Germany)“Momentum-resolved hard x-ray photoemission and photoelectron diffraction
using time-of-flight recording” (On-line)

19:00 - 19:15

Andreas Lindblad (Uppsala University, Sweden)“First results from the HAXPES-lab@UU facility” (On-line)

19:15 - 19:30

Julius Hållstedt (Excillum AB, Sweden)“High performance X-ray sources for X-ray photoelectron spectroscopy”(On-line)

19:30 - 20:00

Invited talkChristoph Schlueter (Deutsches Elektronen-Synchrotron DEZY, Germany)“HAXPES at PETRA III and IV: electronic structure, operando devices and insitu catalysis” (On-line)

20:00 - 20:15

Vladimir N. Strocov (Swiss Light Source, Switzerland)“k-resolved electronic structure and band offsets at the NbN/GaN
superconductor/semiconductor heterojunction” (On-line)

20:15 - 20:30

Martina Müller (University of Konstanz, Germany)“How dopants and defects stabilize ferroelectricity in HfO2 - a spectroscopic
approach” (On-line)

17:30 - 18:00

Dinner & Night session

Wednesday, 1 June, Arcrea Himeji (Himeji Convention Center)
Chair: Shigenori Ueda
9:00 - 9:30

Invited talk
Hidenori Fujiwara (Osaka University, Japan)“Probing spin-polarized electronic structures on half-metallic Heusler alloys
using combined bulk-sensitive spectroscopies”

9:30 - 9:45

Alexander X. Gray (Temple University, USA)
“Probing strain-engineered anion ordering via depth-sensitive and polarizationdependent X-ray spectroscopic techniques” (On-line)

9:45 - 10:00

Munetaka Taguchi (Toshiba Nanoanalysis Corporation, Japan)“Total reflection hard X-ray photoelectron spectroscopy for La1-xSrxMnO3 andLa1.9Ce0.1CuO4”

10:00 ‒ 10:15

Short break

Chair: Kojiro Mimura
10:15 - 10:45

Invited Talk
Eric L. Shirley (National Institute of Standards and Technology, USA)
“Theoretical aspects of resonant Auger processes in solids” (On-line)

10:45 - 11:00

Hsun-Yun Chang (ULVAC-PHI Inc., Japan)“Accurate and non-destructive layer structure analysis of semiconductormaterials using angle resolved HAXPES”

11:00 - 11:15

Trung-Phuc Vo (University of West Bohemia, Czech Republic)“Theoretical and experimental HARPES study of Weyl-semimetal TaAs: The
application of machine-learning” (On-line)

11:15 - 11:30

Dirk Hauschild (Karlsruhe Institute of Technology, Germany)“Core-level peaks and the inelastic background in HAXPES: a depth-resolved
analysis of the CdS/Cu(In,Ga)Se2 interface for thin-film solar cells”

11:30 ‒ 13:00

Lunch session

13:00 ‒ 14:00

Company presentation

Chair: Satoshi Yasuno
13:00 - 13:15

Andreas Thissen (SPECS, Germany)“From SXPS to HAXPES ‒ instrumentation andapplications of surface and bulk chemical
analysis in the laboratory”

13:15 - 13:30

Marten Patt (FOCUS GmbH, Germany)“NanoESCA, HAXPEEM, xTOF ‒ An evolutionin hard x-ray microscopy” (On-line)

13:30 - 13:45

Peter Amann (Scienta Omicron, Sweden)“Hard X-ray photoemission spectroscopy
possibilities at Scienta Omicron” (On-line)

13:45 - 14:00

Yoshio Ichii (Jtec Corporation, Japan)”New Optical Devices for
Next-Generation Synchrotron Facilities”

14:00 ‒ 14:15

Short break

Chair: Munetaka Taguchi
14:15 - 14:45

Invited Talk
Atsushi Hariki (Osaka Metropolitan University, Japan)“LDA+DMFT approach to core-level x-ray spectroscopies in correlated
electron systems”

14:45 - 15:00

J. Matthias Kahk (University of Tartu, Estonia)“Theoretical prediction of core electron binding energies using themethod-application to 3d transition metals” (On-line)

15:00 - 15:15

15:15 ‒ 15:45

SCF

Victor Kimberg (KTH Royal Institute of Technology, Sweden)“Time-resolved study of recoil-induced rotation by X-ray pump - X-ray probe
spectroscopy”

Coffee breakChair: (TBD)
15:45 - 16:30

Plenary Talk
Michael Sing (Julius-Maximiliians-Universität Würzburg, Germany）“Hard x-ray photoelectron spectroscopy of functional oxide films andheterointerfaces”(On-line)

16:30 - 16:45

Jan Minar (University of West Bohemia, Czech Republic)“Proximity-induced spin-orbit interaction in MoSe2 overlayered withamorphous Pb films ”(On-line)

16:45 - 17:00

Fredrik O.L. Johansson (Sorbonne Universite, France)“Studying anisotropic electronic structure in 2D-layered crystals using
resonant Auger spectroscopy” (On-line)

17:00 - 17:15

Curran Kalha (University of College London, UK)“Dynamic SXPS and HAXPES study of the thermal stability of TixW1-x/Cu
heterostructures” (On-line)

17:15 ‒ 17:30

Short break

Chair: Eiji Ikenaga
17:30 - 17:45

Jean Pascal Rueff (Synchrotron SOLEIL, France)“Probing quantum materials interfaces with HAXPES at the GALAXIES
beamline : results and perspectives” (On-line)

17:45 - 18:00

Daisuke Takegami (Max Planck Institute Chemical Physics of Solids, Germany)“CaCu3Ru4O12 : a high Kondo-temperature transition metal oxide”

18:00 - 18:15

Pierre-Marie Deleuze (Université Grenoble-Alpes, France)“Lab-Scale hard X-ray photoelectron spectroscopy for the analysis of buriedinterfaces in device technologies” (On-line)

18:15 - 18:30

Sunil Wilfred DSouza (University of West Bohemia, Czech Republic)“Metallic antiferromagnetic spintronics: Mn2Au a case study”(On-line)Memorial Talk
18:30 - 18:45

Memorial Talk
Charles Fadley & Yasutaka Takata

18:45 ‒ 20:30

Dinner & Poster session

Chair: Ralph Claessen
20:30 - 21:00

Invited Talk
Marcus Bär (Helmholtz-Zentrum Berlin für Materialien und Energie GmbH,Germany)“Materials research for metal-halide Perovskite solar cells enabled by hard xray photoelectron spectroscopy”

21:00 - 21:15

Austin Irish (Lund University, Sweden)“Characterization of ferroelectric devices: HfZrO thin films on InAs”(On-line)

21:15 - 21:30

Jay R. Paudel (Temple University, USA)
“Combining depth-sensitive X-ray spectroscopic and scattering techniques toprobe interfacial magnetic phenomena in oxide superlattices”(On-line)Thursday, 2 June, Arcrea Himeji (Himeji Convention Center)
Chair: Alexander Gray
9:00 - 9:30

Invited Talk
Slavomir Nemsak (Advanced Light Source, USA)
“Using X-ray optical effects in photoelectron spectroscopy to study
heterogeneous systems”(On-line)

9:30 - 10:00

Invited Talk
Shigenori Ueda (National Institute for Materials Science, Japan)“New dimensions of HAXPES: variable polarization, total reflection, and spin
resolution”

10:00 - 10:15

Yoshiyuki Yamashita (National Institute for Materials Science, Japan)“Gap states at SiO2/4H-SiC interface obtained from operando hard x-ray
photoelectron spectroscopy”

10:15 - 10:30

Lothar Weinhardt (Karlsruhe Institute of Technology)“X-SPEC : A 70eV to 15keV undulator beamline for electron and x-ray
spectroscopies”

10:30 - 11:00

Invited Talk
Akira Yasui (Japan Synchrotron Radiation Research Institute, Japan)“Upgrading of a HAXPES beamline BL09XU of SPring-8”

11:00 ‒ 14:30

Open discussion & Lunch

Chair: Masaki Oura

14:30 - 15:00

Invited Talk
Stephen H. Southworth (Argonne National laboratory, USA)
“Atomic inner-shell resonance, threshold, and double ionization studies”(On-line)

15:00 - 15:15

Minna Patanen (University of Oulu, Finland)“First HAXPES results on clusters : K-shell photoexcitation and subsequent
electronic decays in Ar clusters” (On-line)15:15 - 15:30

Faris Gelmukhanov (KTH Royal Institute of Technology, Sweden)“Translational and rotational recoil effects in HAXPES of free molecules”

15:30 - 16:15

Plenary Talk
Marc Simon (CNRS & Sorbonne University, France)“Gas phase HAXPES studies” (On-line)

16:15 ‒ 16:45

Coffee break

Chair: Tien-Lin Lee
16:45 - 17:00

Natalia M. Martin (Uppsala University, Sweden)“Depth-resolved HAXPES study of (Ag,Cu)(In,Ga)Se2 thin film solar cells”(On-line)

17:00 - 17:15

Andrew J. Naylor (Uppsala University, Sweden)“Using hard X-ray photoelectron spectroscopy to probe rechargeable battery
interfaces” (On-line)

17:15 - 17:45

Invited Talk
Sara Blomberg (Lund University, Sweden)“Operando high pressure catalytic studies using HAXPES” (On-line)

17:45 - 18:00

Patrick Lömker (Stockholm University, Sweden)“Co(0001) Fischer-Tropsch observations at 550mbar (and above) using avirtual cell approach and hard x-rays” (On-line)

18:00 - 18:15

Eugenie Martinez (Université Grenoble Alpes, France)“Laboratory HAXPES of GaN structures for power electronics”(On-line)

18:15 - 18:30

Dibya Phuyal (KTH - Royal Institute of Technology, Sweden)“Strong dimensional character in layered ReS2 and ReSe studied bycomplimentary X-ray photoelectron spectroscopy” (On-line)

18:30 ‒ 21:00
21:30 ‒ 22:30

Dinner session
International Advisory Board (IAB) meeting

Friday, 3 June, Arcrea Himeji (Himeji Convention Center)
Chair: Yoshiyuki Yamashita
9:00 - 9:45

Plenary Talk
Bongjin Simon Mun (Gwangju Institute of Science and Technology, Korea)“Exploring surface catalytic nature with ambient pressure XPS”
(On-line)

9:45 - 10:15

Invited Talk
Kelvin Zhang (Xiamen University, China)“The electronic structure of degenerately doped Ga2O3 thin files studied by
HAXPES” (On-line)

10:15 ‒ 11:00

Breakout session

11:00 ‒ 12:00

Closing
Concluding remarks by Wolfgang Drube
Next venue

Poster session

P01

Resonant Auger of Xe on transition metal substrates
Elin Berggren ‒ Uppsala University (On-line)

P02

In-plane orientation of the 4f-orbital distribution in YbRh2Si2 probed bylinear dichroism in core-level HAXPES
Akane Ose ‒ Osaka University

P03

Magnetometry of buried Co-based nanolayers by hard x-ray photoelectron
spectroscopy
Andrei Hloskovsky ‒ DESY (On-line)

P04

Bulk electronic state of Au-Ga-Ce and Cd-Ce quasicrystalline approximants
probed by hard x-ray photoemission spectroscopy
Goro Nozue ‒ Osaka University

P05

Electronic structure of thermoelectric Heusler-type Co2MnSi1-xAlx
compounds
Hidetoshi Miyazaki ‒ Nagoya Institute of Technology

P06

Valence fluctuation in thermoeletric material YbSi2 probed by HAXPES
Kentaro Kuga ‒ Toyota Technological Institute

P07

Relationship of Ce 4f-5d coulomb repulsion on CeT2X2 (T=Cu,Ru; X=Si,Ge):
resonant HAXPES study
Kojiro Mimura ‒ Osaka Metropolitan University

P08

Charge transfer energy in iridates : a hard X-ray photoelectron
spectroscopy study
Liu Hao Tjeng ‒ Max Planck Institute Chemical Physics of Solids (On-line)

P09

Observation of ferroelectric skewed band structure in multiferroic BiFeO3
Shibei Huang ‒ Okayama University

P10

Dy 3d core-level photoemission lineshape and its correspondence withchemical state
Shin Imada ‒ Ritsumeikan University

P11

Resonant hard x-ray photoemission on valence fluctuating system α-Yb(Al1xFex)B4
Takuma H. Nishioka ‒ Osaka University

P12

Systematic charge distribution changes in Bi, Pb-3d transition metal
perovskite oxides
Takumi Nishikubo ‒ Kanagawa Institute of Industrial Science andTechnology

P13

Electronic states of FeGa alloy studied by hard and soft x-ray photoelectron
spectroscopy
Tetsuya Miyazaki ‒ Ritsumeikan University

Poster session

P14

Electronic structure of covalent-chain antiferromagnets TlFeX2 (X=S,Se)
studied by HAXPES
Tomoki Shinozuka ‒ Osaka Metropolitan University

P15

Electronic states of type-II Na-Ba-Si clathrete studied by hard x-ray
photoelectron spectroscopy
Yuchen Chen ‒ Ritsumeikan University

P16

Ir 5d state of CuIr2S4 studied by Ir 2p3/2-5d resonant HAXPES
Yukihiro Taguchi ‒ Osaka Metropolitan University (On-line)

P17

Electronic structure of Co2NbSn studied by hard x-ray photoelectron
spectroscopy
Yuuki Shimada ‒ Ritsumeikan University

P18

Trial of hard x-ray photoemission electron microscopy (HAXPEEM) at
SPring-8
Satoru Hamamoto ‒ RIKEN SPring-8 Center

P19

Ground state symmetry of rare-earth ions and emission angle dependence
in resonant x-ray photoemission
Hisashi Soma ‒ Osaka Prefecture University

P20

Core-level photoemission spectroscopy of 3d transition metal oxides :DFT+DMFT analysis
Keisuke Higashi ‒ Osaka Prefecture University

P21

Design of an in-situ, in-operando HAXPES cell for the characterization of
SEI formation in Li-ion batteries
Federico Giovanni Capone ‒ PHENIX Lab., Sorbonne Universite

P22

APXPS study on Pt3Pd3Sn2/C catalyst for dimethyl ether oxidation
Jan Minar ‒ University of West Bohemia

P23First HAXPES studies of photovoltaic materials at EMIL: depth-resolved
structure of (Ag,Cu)(In,Ga)Se2
Regan G. Wilks ‒ Helmholtz-Zentrum Berlin fur Materialien und Energie
GmbH

P24

HZB energy materials research at SPring-8 BL15XU 2018-2019
Regan G. Wilks ‒ Helmholtz-Zentrum Berlin fur Materialien und Energie
GmbH

P25

X-ray spectroscopic study of the electronic states of Pd nanoparticles
Satoshi Ogawa ‒ Nagoya University

P26

Spectroscopic study and photocatalytic activity of Au-Ni nanoparticles forhydrogen production reaction by water splitting
Takumi Kawaguchi ‒ Nagoya University

Poster session

P27

The "Two-Color" EMIL beamline at the BESSY II light source
Mihaela Gorgoi ‒ Helmholtz-Zentrum Berlin fur Materialien und EnergieGmbH (On-line)

P28

Effects of Sample-Aperture Cone Distance on Environmental Charge
Compensation in Hard X-ray Photoelectron
Satoru Suzuki ‒ LASTI, University of Hyogo (On-line)

P29

Hard x-ray photoelectron spectroscopy beamline designed at Shenzhen
Innovation Light-Source Facility (SILF)
Tianhui Liu ‒ Institute of Advanced Science Facilities (On-line)

P30

Three-dimensional spatial-resolved HAXPES measurement using a 1 mm
focused beam
Yasumasa Takagi ‒ Japan Synchrotron Radiation Research Institute

P31

The operande measurement for bias applied technique using laboratory
based hard x-ray photoelectron spectroscopy with Ga Ka x-ray source
Tappei Nishihara ‒ Meiji University

P32

Study on the relationship between chemical structure and function ofamphiphilic gel surface
Eri Ito ‒ Nagoya Institute of Technology

Sponsor companies

HAXPES Lab

A Window to the Bulk

HAXPES Lab Features: ĞƐƚƌƵĐƟŽŶĨƌĞĞŝŶĨŽƌŵĂƟŽŶĨƌŽŵĚĞĞƉďĞůŽǁƚŚĞƐƵƌĨĂĐĞ ĞƐŝŐŶĞĚĨŽƌĨĂƐƚĚĂƚĂĂĐƋƵŝƐŝƟŽŶ
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www.ScientaOmicron.com

Hard X-ray photoemission spectroscopy possibilities at
Scienta Omicron
P. Amann1,2, M. Masatake3, P. Palmgren1, T. Wiell1, M. Lundwall1, S. Eriksson1
1
Scienta Omicron AB, Danmarksgatan 22, 75323 Uppsala, Sweden
2
Scienta Omicron GmbH, Limburger Strasse 75, 65232 Taunusstein, Germany
3
Scienta Omicron, Inc., 6–17–10, MinamiOi, Shinagawa-ku, Tokyo 140–0013, Japan
X-ray photoemission spectroscopy (XPS) using photons from Al KD is a powerful method to investigate the chemical
nature of surfaces. However, the investigation of buried interfaces occurring in, e.g., device electronics or the work withelevated pressure or solid-liquid interfaces is difficult as the energy of the created photoelectrons is not high enough andscattering inside the material bulk limit the detected signal intensity.
During the past decade, increased attention has been shown to hard X-rays in the photoelectron spectroscopy field [1].
This opens a path towards increased information depth and allows probing high binding energy core levels.
In this talk I will give an overview on the Scienta Omicron products: HAXPES Lab, BAR XPS and HiPPHAXPES Lab.
The HAXPES Lab is a high-end laboratory based setup featuring a monochromated X-ray source creating Ga KD
radiation at 9.25 keV and a dedicated electron analyser with +/- 30° wide acceptance angle [2,3]. With this novel basesystem, the investigation of buried interfaces becomes possible. The increased probing depth allows for destruction free
investigation of device electronics making operando measurements attractive.
The BAR XPS is a dedicated ambient pressure HAXPES synchrotron end-station that integrates the virtual cellconcept and allows for operation under unprecedented high-pressure conditions [4].

Grazing incidence spectroscopy

allows for high surface sensitivity and the small cell volume of below ca. 0,1 mm3 allows for fast gas exchange times atthe sample allowing to investigate catalyst dynamics.
The HiPPHAXPES Lab combines the features of the HAXPES Lab and the Bar XPS in a laboratory based ambientpressure instrument. This is made possible by the small spot size of the Ga X-ray source of about 30 x 45 µm2, which is
combined with the ambient pressure HiPP-2 Analyser allowing for operation up to 10 keV.

[1]

C. Kalha, N.K. Fernando, P. Bhatt, F.O.L. Johansson, A. Lindblad, H. Rensmo, L.Z. Medina, R. Lindblad, S.
Siol, L.P.H. Jeurgens, C. Cancellieri, K. Rossnagel, K. Medjanik, G. Schonhense, M. Simon, A.X. Gray, S.
Nemsak, P. Lomker, C. Schlueter, A. Regoutz, J. Phys. Condens. Matter 33 (2021) 233001.

[2]

A. Regoutz, M. Mascheck, T. Wiell, S.K. Eriksson, C. Liljenberg, K. Tetzner, B.A.D. Williamson, D.O.
Scanlon, P. Palmgren, Rev. Sci. Instrum. 89 (2018).

[3]

T. Hashimoto, P. Amann, A. Regoutz, N. Barrett, L.F.J. Piper, W. Hamouda, O. Renault, M. Lundwall, M.
Masatake, Vac. Surf. Sci. 64 (2021) 493–498.

[4]

P. Amann, D. Degerman, M.-T. Lee, J.D. Alexander, M. Shipilin, H.-Y. Wang, F. Cavalca, M. Weston, J.
Gladh, M. Blom, M. Björkhage, P. Löfgren, C. Schlueter, P. Loemker, K. Ederer, W. Drube, H. Noei, J.
Zehetner, H. Wentzel, J. Åhlund, A. Nilsson, Rev. Sci. Instrum. 90 (2019) 103102.

Pioneering New Horizons in Science
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NanoESCA, HAXPEEM, xTOF – An evolutionin hard x-ray microscopy
Marten Patt1, Nils Weber1, Matthias Escher1, Michael Merkel1
1FOCUS GmbH, 65510 Hünstetten, Germany

The NanoESCA was initially developed as photoemission electron microscope (PEEM) for real-space
imaging, combined with a powerful double-hemispherical energy band-pass filter. As such it is already apowerful tool for work function mapping and for chemical imaging of nanostructured samples withunsurpassed lateral resolution (if combined with an x-ray source) [1]. Soon after, the concept was extended
to image the momentum distribution of the photoelectrons [2], generally excited by VUV sources. The
combination of energy-filtered real-space and momentum-space microscopy makes it the most versatile
photoemission instruments of today, addressing the questions of future device engineering with respect totheir chemical states or electronic properties. Micro-ARPES becomes possible by isolating a small regionof interest in real-space with an aperture while projecting the full angular distribution of electrons from thisregion onto the imaging detector unit.
To take advantage of the higher probing depth of HAXPES experiments, the NanoESCA was extended towork with high kinetic energy electrons. This HAXPEEM experiment allows for chemical and lateral resolved
images of active layers beneath a top electrode [3], making it a promising technique for the analysis of
microstructured and layered samples in material science and microelectronics [4].
An increase of efficiency of the HAXPEEM approach can be reached by combining the doublehemispherical band-pass filter of the NanoESCA with an imaging time-of-flight detector, i.e. a delay line
detector. While the latter allows for parallel detection of lateral and energy coordinates, the upstream bandpass filter cuts off unwanted energies and avoids overlapping spectra generated from subsequent pulses
at high repetition rates. We will present the concept and initial proof-of-principal measurements of thispatented new xTOF approach [5, 6].

References[1] O. Renault et al., J. Electron Spectrosc. Relat. Phenom. 171, 68 (2009)[2] B. Krömker et al., Rev. Sci. Instrum. 79, 053702 (2008)[3] M. Patt et al., Rev. Sci. Instrum. 85, 113704 (2014)[4] C. Kalha et al., J. Phys.: Condens. Matter 33, 233001 (2021)[5] N. Weber, German Patent DE 10 2017 009 299 C5 (2017)[6] G. Schönhense et al., Rev Sci. Instrum. 91, 123110 (2020)

HAXPES Instrumentation
SOURCES AND ANALYZERS FOR CHEMICAL COMPOSITION STUDIES OFSURFACES AND BULK MATERIALS IN LABORATORY ENVIRONMENTSKEY FEATURES• High transmission analyzer series for kinetic
energies up to 7 keV, 10 keV and 15 keV• Small spot X-ray monochromator sources
with highest flux densities for any combination of Al Kž, Ag Lž and Cr Kž• Flexible but proven system integration
for any customer application• Available for UHV (10-11ɋmbar) to Near Ambient Pressure (up to 200 mbar) conditions

SPECS Surface Nano Analysis GmbHT +49 (0)30 46 78 24-0ɅE info@specs.comɅH www.specs.com

A member of SPECSGROUP
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Sales Oႈce Shin-Osaka Kita Building, 4-1-46 Miyahara, Yodogawa-ku, Osaka 532-0003, 06-6393-7411

www.tokyoinst.co.jp
sales@tokyoinst.co.jp

Expanding our global network to provide cutting-edge science to our customers!

From SXPS to HAXPES –instrumentation and applications of surface and bulk
chemical analysis in the laboratory
Andreas Thissen 1, Deler Langenberg 1
1

SPECS Surface Nano Anaysis GmbH, Voltastr. 5, 13355 Berlin, Germany

In recent years, there has been an increasing demand in hard X-ray photoelectron
spectroscopy (HAXPES) depth and operand measurements in the study of devices especiallythe bulk and interface characteristics.
To gain access to the bulk and interface states of the material, it is necessary to increase thekinetic energy of the photoelectrons using high-energy X-rays. The photon energies of HAXPES
typically range from 3 to 15 keV, and information can be obtained from depths of up to 100 Å.
Therefore, it is particularly effective for extracting information on electronic and magnetic statesfrom the inner shell spectrum in materials with greatly different surface and bulk properties, suchas thin films and strongly correlated materials.
However, special consideration is required for the equipment due to the low
photoionization cross section at high excitation energies. Therefore, a light source with highphoton density and efficient electron detection are important.
In this announcement, we will introduce various HAXPES products from SPECS.

Fig. 1: sources and analyzers for chemical composition studies of surfaces and bulk materials inlaboratory environments.

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Abstract
Oral session

31n1-1 : Plenary

Momentum-resolved hard X-ray photoemission andphotoelectron diffraction using time-of-flight recording
Gerd Schönhense
Johannes Gutenberg University, Inst. of Physics, Staudingerweg 7, D-55128 Mainz, Germany
Momentum microscopy (MM) is a novel way of performing ARPES. Combined with time-offlight (ToF) recording, its high parallelization is advantageous for photon-hungry
experiments like X-ray ARPES, spin-resolved and time-resolved ARPES. Here we introduce
the technique and illustrate its performance by selected examples obtained at hard X-ray
energies. High-energy MM uses the same recording scheme as the low-energy variant [1], but
a new electron optics enables energies up to >7keV and large k-fields-of-view comprising up totens of Brillouin zones (BZs). Next to valence-band mapping, effective recording of XPD
patterns [2] yields structural information. The new microscope can host an imaging spin filter;for details, see [3].
Fig. 1 shows an example for the Kondo system YbRh2Si2, where fast 4D mapping revealed thetemperature dependence of the Fermi surface [4]. The XPD pattern (a) shows the two (110)-type
Kikuchi bands (width 3.1Å 1 given by the reciprocal lattice vector 2G110). The k-field of >12 Å 1
corresponds to five adjacent BZs. This enables capturing the full 3D-dispersion of valence bands
without changing photon energy. The perpendicular momentum component along kz decreases
with increasing parallel momentum kx, Fig. 1(b,c). The energy conservation law forces all final
states on an energy isosphere with radius kf. Due to the curvature, kz covers a ange of kz=0.5G001 in one experimental run at fixed h . Precise setting to h =5297eV yields _kf_=29 G001, so thatin the image center the sphere intersects the 29th repeated BZ through the *-point. With
increasing radius, kz continuously drops toward the border of the 5th BZ, Fig. 1(c). The energy
isosurfaces in (kx,ky,kz) (d) have been captured at a single photon energy of h =5297 eV [4,3].
First fs time-resolved measurements have been performed using soft X-rays at FLASH [5].

Fig. 1: Hard-X-ray analysis of the Kondo system YbRh2Si2. (a) XPD at the Yb 4f level probes thegeometric structure and provides a metric in k-space. (b,c) The final-state energy isosphere intersects
adjacent BZs at different kz, accessing the full 3D energy isosurfaces (d) without changing photon energy.

References[1] K. Medjanik et al., Nature Mat. 16, 615 (2017).
[2] O. Fedchenko et al., J. Phys. Soc. Jap., under review; e-print arXiv 2202.11951 (2022).
[3] G. Schönhense and H. J. Elmers, J. Vac. Sci. Technol. A 40, 020802 (2022).
[4] S. Agustsson et al., J. Phys. Condens. Matter 33, 205601 (2021).
[5] F. Pressacco et al., Nature Commun. 12, 5088 (2021).

31n1-2 : Contributed

First results from the HAXPES-lab@UU facility
Andreas Lindblad1
1 X-ray Photon Science/Dept. Physics & Astronomy, Uppsala University, SE-75120 Uppsala,SwedenAn in-house HAXPES-lab facility built up around a liquid metal jet (Ga KD) hard X-ray and an
Al KD soft X-ray source have been recently established at our department in Uppsala. Since theinstrument is meant to study a broad range of materials physics problems – from fundamental
interface properties to applied studies of e.g. batteries and photovoltaics in operando, thecapabilities of the system needs to be implemented with this in mind from the outset. I
will present the first results from the system together with how the facility fits with other hard/tender X-ray PES initiatives in Sweden and our roadmap to develop the facility
further with complementary capabilities.

31n1-3 : Contributed

High performance X-ray sources for X-ray photoelectron
spectrocopy
Julius Hållstedt
Excillum AB, Jan Stenbecks Torg 17, 164 40 Kista, SwedenHigh end X-ray photoelectron spectroscopy (XPS) relies heavily on the X-ray source
performance for the analytical output. In principle there is a trade off between X-ray flux,
monochromatizating and beam size which traditionally has especially for hard energy XPS(HAXPES) led to very long measurement times and poor signal to noise. In the recent years
however, X-ray sources based on liquid-metal-jet technology (MetalJet) has successfully been
introduced into HAXPES community in many labs across the globe. The increased power loading
capability from MetalJet sources is explained by the fact the electrons are in MetalJet sources
impinging on a continuously generated liquid alloy compared to a static solid anode in standard
X-ray tubes, see fig 1. This significantly increase X-ray brightness and enables small X-ray spots
in combination with high powers. This has enabled the electron spectroscopist with theconvenience of HAXPES home lab capability in combination with excellent analytical results atshort measurement times [1].
This communication will discuss the recent development with the MetalJet technology, its
scalability, suitability and future potential for electron spectroscopy. We will also present recent
result how total power has increased with a factor four (4) compared to first generation MetalJets[2]. Finally, the potential usage of both new high end solid and liquid anode X-ray sources forgeneral XPS will be addressed.

Fig. 1: The principle of a solid anode X-ray tube (a) and a liquid-metal-jet X-ray tube (b).

References[1] Curran Kalha et al 2021 J. Phys.: Condens. Matter 33 233001[2] https://www.excillum.com/our-products/metaljet/metaljet-e1-160-kv/

31n1-4 : Invited

HAXPES at PETRA III and IV: electronic structure,operando devices and in-situ catalysis
Christoph Schlueter1, Andrei Gloskovskii1, Yury Matveyev1, Patrick Lömker1,5,
Thiago Peixoto1, Katrin Ederer1, Ilja Schostak1, Michael Sing2, Ralph Claessen2,
Carsten Wiemann3, Claus M. Schneider3, Katerina Medjanik4, Gerd Schönhense4,
Peter Amann5, Anders Nilsson5 and Wolfgang Drube1
1
2

Photon Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany,

Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany,
3Peter Grünberg Institut, Forschungszentrum Jülich, 52425 Jülich, Germany,
4
Institut für Physik, Johannes Gutenberg-Universität, Mainz, Germany,
5
Department of Physics, AlbaNova University Center, Stockholm University, S-10691
Stockholm, Sweden

In September 2018, the X-ray undulator beamline (P22), fully dedicated to hard X-ray
photoelectron spectroscopy (HAXPES) techniques, opened to users at PETRA III. The beamline
hosts four specialised experimental end stations for high-resolution studies of the electronic andchemical structure of complex materials, realistic device-like structures and catalytic interfaces.
The main instrument for conventional HAXPES techniques offers sample cooling and in-situ
electrical characterisation for operando studies. A separate instrument provides full-field, sub-μm
electron spectro-microscopy (HAXPEEM). Additionally, a specialized setup for high-pressure
HAXPES applications (POLARIS) recently demonstrated its capabilities at pressures >2.0 bar.
Finally, a full-field k-microscope with time-of-flight energy discrimination delivered first fully kresolved valence band structures in the HAXPES energy range (up to 7 keV). All instruments are
implemented and operated in close collaboration with external user groups and as such reflect thewide range of scientific fields currently covered by our community.
References[1] C. Schlueter, A. Gloskovskii, et al. AIP conference proceedings 2054(1), 040010 (2019)[2] C. Schlueter, A. Gloskovskii, et al. Synchrotron Radiation News 31, 29–35 (2018)

31n1-5 : Contributed

k-resolved electronic structure and band offsets at the
NbN/GaN superconductor/semiconductor heterojunction
Tianlun Yu1,2, John Wright3, Guru Khalsa3, Betül Pamuk4, Celesta S. Chang5, Yury
Matveyev6, Xiaoqiang Wang1, Thorsten Schmitt1, Donglai Feng7,8,9, David A.
Muller5,10, Huili Grace Xing10,11, Debdeep Jena10,11, Vladimir N. Strocov1
1

Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
2
Department of Physics, Fudan University, Shanghai 200433, China
3
Materials Science and Engineering, Cornell University, Ithaca, NY 14850, USA
4
PARADIM, Cornell University, Ithaca, NY 14853, USA
5
School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
6
Photon Science, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
7
Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
8
Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
9
University of Science and Technology of China, Hefei 230026, China
10
Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853, USA
11
Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.
Electronic structure of heterointerfaces plays a pivotal role in their device functionality. Recently,
ultrathin films of superconducting NbN (Tc=17K) have been integrated by MBE with thesemiconducting GaN. To directly
measure k-resolved electronic structure
and band offsets at this Schottky
heterointerface as well as the bandbending profile into GaN, we use soft Xray ARPES at the ADRESS beamline of
the Swiss Light Source. With different
out-of-plane lattice constants of NbN
and GaN, our experiment uses different
photon energies to probe electronic
structure at the opposite sides of theinterface. We support the experimental Fig. 1: Experimental band structure of NbN matched tofindings with DFT calculations as well as GaN at the interface.
transport and optical measurements.
Most importantly, we find that the Fermi states of NbN are well separated from the GaN states inenergy and k, excluding their crosstalk and thus poisoning of the superconductivity in NbN by the
GaN electrons. This finding opens prospects of integrating NbN-based superconducting devices(single-photon detectors, Josephson junctions, etc) into semiconductor technology.

References[1] Tianlun Yu et al, Sci. Adv. 7, eabi5833 (2021)

31n1-6 : Contributed

How dopants and defects stabilize ferroelectricity in HfO2 –a spectroscopic approachThomas Szyjka1,2, Lutz Baumgarten 2, Terence Mittmann3, Monica Materano3,
Yury Matveyev4, Christoph Schlueter4, Thomas Mikolajick3, Uwe Schroeder3, andMartina Müller1
1
University of Konstanz, Department of Physics, Universitätsstr. 10, 78457 Konstanz, Germany
2

Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), Leo-Brandt Strasse, 52425
Jülich, Germany
3
NaMLab gGmbH, Noethnitzer Str. 64a, 01187 Dresden, Germany
4
Deutsches Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg, Germany

HfO2 is a key multifunctional material for nonvolatile ferroelectric field effect transistors,
memristors or novel neuromorphic computing concepts. Oxygen vacancies and metallic impurity
ions are recognized as defects which both can stabilize the ferroelectric phase in undoped HfO2.
HAXPES provides a unique tool to explore the interface reactivity and tunability of the oxygen
content in HfO2-based devices. We present studies on the emerging chemical states of HfO2based capacitors and focus on the identification of the (mostly indirect) signatures of oxygen
vacancies or rare-earth dopants in the HfO2 layers and at the metal electrode interfaces [1].
We correlate HAXPES data recorded at the beamline P22 (DESY Hamburg, Germany) toelectric field cycling experiments, and conclude on how the microscopic HfO2 electronic
structure directly relates to macroscopic ferroelectric polarization and switching properties. We
show selected examples which reval the different interface oxygen exchange mechanisms in
HfO2-metal electrode structures [2], demonstrate the oxygen vacancy formation in HfO2 layers
dependent on rapid thermal annealing processes [3], as well as oxygen vacancy/nitrogen impurity
interactions altered by deposition-specific parameters [4].
References[1] M. Müller et al., J. Vac. Sci. Technol. A 40, 013215 (2022), DOI: 10.1116/6.0001491[2] T. Szyjka, L. Baumgarten, M. Müller et al, ACS Appl. Electr. Mat. 8, 111102 (2020), DOI: 10.1063/5.00221[3] T. Szyjka, L. Baumgarten, M. Müller et al., phys. stat. solidi RRL 18, 2 (2021), DOI: 10.1002/pssr.202100012[4] L. Baumgarten, T. Szyjka, M. Müller et al., Appl. Phys. Lett 118, 032903 (2021), DOI: 10.1063/5.0035686

1a1-1 : Invited

Probing spin-polarized electronic structures on half-metallic
Heusler alloys using combined bulk-sensitive spectroscopies
Hidenori Fujiwara
Grad. Sch. of Eng. Sci., Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan

Toward the next generation spintronic application using the spin-degrees of freedom, it is essential tooptimize the spin-polarized electronic structures of the spintronic materials. The Halfmetallic
Heusler alloys [1] are candidates of the spintronic materials, since one of the spin-subbands is
metallic and the other is semiconducting with a gap at the EF predicted by the density functional theory(DFT). However, it is not straightforward to reveal the intrinsic electronic structures of Heusler
alloys, since it is well known that the off-stoichometric effects and various disorder often change themagnetic properties and the local electronic structures.
To reveal the intrinsic spin-polarized electronic structures of halfmetallic Heusler alloys, wehave conducted combined bulk-sensitive spectroscopies for high-quality single-crystalline
samples of ferromagnetic Co2MnSi, Co2FeSi and ferrimagnetic Mn2VAl using linearlypolarized hard x-ray photoelectron spectroscopy (HAXPES), soft x-ray absorption spectroscopy(XAS), and resonant inelastic soft x-ray scattering (RIXS). HAXPES measurements have been
performed at SPring-8 BL19LXU, where transmission-type phase retarders were installed [2,3].
Moreover, XAS-MCD [4,5] and RIXS-MCD [5,6] were performed at SPring-8 BL23SU and
BL07LSU, respectively.
The valence band HAXPES obtained with s-polarization configuration is nicely described by
the simulation based on the weighted sum of the partial density of states by taking into
account the asymmetry factors of the photoionization cross-section. Moreover, the RIXS-MCD
experiments under the external magnetic field probes the intrinsic spin-polarized electronic structures
thanks to the spin-conserved dipole-allowed transition from the spin-polarized 2p3/2 mj = r3/2 states[5,6,7]. The strong MCD contrast in the RIXS-MCD spectra for Co2MnSi, Co2FeSi and Mn2VAl
reflect the up and down spin contribution of the 3d states in the positive and negative MCD
signals. These RIXS-MCD spectra are also qualitatively explained by the DFT-based simulation as
well as HAXPES and XAS-MCD spectra. By using the combination of the advanced spectroscopies,
we have successfully proved the halfmetallic electronic structures of Co2MnSi and Mn2VAl. Thissuggests that the multimodal investigation of the electronic structures using the bulk sensitive
spectroscopies are powerful for revealing the detailed spin-polarized electronic structures of thefunctional magnetic materials.
References[1] C. Felser and A. Hirohata, “Heusler Alloys”, Springer Series in Materials Science, Springer-Nature (2016).
[2] H. Fujiwara, et al., J. Synchrotron Rad. 23, 735 (2016).
[3] H. Aratani, H. Fujiwara et al. Phys. Rev. B, 98 12113(R) (2018).
[4] K. Nagai, H. Fujiwara et al., Phys. Rev. B 97, 035143 (2018).
[5] H. Fujiwara, et al., Scientific Reports 11, 18654 (2021)[6] R. Y. Umetsu, H. Fujiwara et al., Phys. Rev. B 99, 134414 (2019).
[7] J. Miyawaki, H. Fujiwara et al., J. Synchrotron Rad. 24, 449 (2017).

1a1-2 : Contributed

Probing strain-engineered anion ordering via depth-sensitiveand polarization-dependent X-ray spectroscopic techniques
Alexander X. Gray1, Jiayi Wang2, Yongjin Shin3, Jay R. Paudel1, Padraic Shafer4,
Vladimir N. Strocov5, James M. Rondinelli3, and Steven J. May1
1

Department of Physics, Temple University, Philadelphia, PA, USA
Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA
3
Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA
4
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
5
Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
2

Inducing atomic-scale ordering in functional heteroanionic materials is a promising approach forrealizing new or enhanced physical properties. In this study, we demonstrate that epitaxial strain
can be used to control F/O ordering in epitaxial SrMnO2.5 F thin films deposited on substrates
with different in-plane lattice constants [1]. By using a complementary suite of lab-based valenceband hard x-ray photoemission (HAXPES), polarization-dependent soft x-ray resonant valenceband photoemission, x-ray linear dichroism, and density functional theory calculations, wedea e ha F cc ie he a ical i ede ce i e ai leadi g
M F b doriented along the out-of-plane direction. In contrast, F is incorporated on equatorial sites under
tensile s ai , leadi g M F b d a allel
he i -plane directions. Such anionic-site selective
substitutions result in changes to the valence-band density of states and lead to an increased
resistivity in films in which F occupies the apical sites compared to those in which F resides at theequatorial position. By demonstrating a general strategy for inducing preferential anion-site
occupancy in oxyfluoride perovskites, this work lays the foundation for future materials designand synthesis efforts that leverage this greater degree of atomic control to realize new polar or
quasi-two-dimensional materials. Furthermore, it highlights new possibilities for combining labbased valence-band HAXPES with resonant and polarization-dependent synchrotron-based
spectroscopic techniques for comprehensive studies of electronic structure in engineered materials.
This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic
Energy Sciences, Materials Sciences, and Engineering Division under Award DE-SC0019297
References[1] J. Wang et al., Chem. Mater. 33, 1811 (2021).

1a1-3 : Contributed

Total Reflection Hard X-ray Photoelectron Spectroscopy forLa1-xSrxMnO3 and La1.9Ce0.1CuO4
Takao Mizutani1, Teruhiko Saze1, Satoshi Tanaka1, Keiko Fujii2, Hideki Matsuoka3,
Masaki Nakao3, Hiroki Wadati3,4,5, Miho Kitamura6, Koji Horiba6, Yoshihiro
Iwasa3, Hiroshi Kumigashira6,7, Masahiko Yoshiki2 and Munetaka Taguchi 1
1

2

7

Toshiba Nanoanalysis Corporation, Kawasaki 212-8583, Japan
Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan3
Department of Applied Physics, University of Tokyo, Bunkyo-ku 113-8656, Japan
4
Graduate School of Material Science, University of Hyogo, Ako-gun 678-1297, Japan
5
Institute of Laser Engineering, Osaka University, Suita, Osaka 5650871, Japan
6
Institute of Materials Structure Science, High Energy Accelerator Research Organization,
Tsukuba 305-0801, Japan
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 9808577, Japan

Over the last decade, the HAXPES technique made a major impact in unraveling the electronic
properties of solids, encompassing a large field of applications, from fundamental to appliedscience. In the present study, we demonstrate that total reflection hard x-ray photoelectron
spectroscopy (TR-HAXPES) is a versatile method for elucidating a difference between surface
and bulk electronic states of strongly correlated electron systems, complementing conventionalbulk sensitive hard x-ray photoelectron spectroscopy (HAXPES). By using the HAXPES in totalreflection (TR) condition, we have revealed the profound differences between surface and bulk
electronic screening and correlation in La1-xSrxMnO3 and the electron doped high-Tc
superconductor La1.9Ce0.1CuO4[1]. From the incidence angle dependence of the spectral line
shapes, we found that the well-screened peaks first discovered by HAXPES[2] almost disappearedat the TR condition. It is crucial that the probing depth at TR condition is several nanometers,
while it is several tens of nanometers at normal condition. The results strongly demonstrate that
this method allows us to measure both surface and bulk electronic states without making any
changes of experimental conditions like the energy resolution, x-ray energy and the beamline.

References[1] T. Mizutani et. al., Phys. Rev. B 103, 205113 (2021).
[2] K. Horiba et. al., Phys. Rev. Lett. 93, 236401 (2004).

1a2-1 : Invited

Theoretical Aspects of Resonant Auger Processes in Solids
Eric L. Shirley1, J. C. Woicik1, C. Weiland1, A. Rumaiz2
12

National Institute of Standards and Technology, Gaithersburg, MD 20899 USA
National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973 USA

Many research opportunities exist at hard x-ray photoelectron spectroscopy(HAXPES) beamlines. These beamlines frequently involve electron analyzers collecting
electrons emitted along the same direction as the incident photon polarization for linearlypolarized light. X-ray absorption spectroscopy (XAS) measures photoexcitation from eachcore subshell, e.g., L3, M5. XAS sums over orbitals, and contributions by each orbital might
not be revealed using XAS alone. In addition, while partial densities of unoccupied states(e.g., d states with T2g or Eg symmetry) can be different, it may be hard to distinguish between
excitations into various states. Resonant Auger electron spectroscopy also probes unoccupied
states, because an incident x-ray photon energy can be shared by an Auger electron, a twohole final state that follows Auger decay, and a spectator photoelectron. If a spectator
photoelectron was excited with too much or too little energy to achieve its final state, an energy
surplus or deficit can be carried off or paid back by the Auger electron, as revealed in kineticenergy distributions intrinsic to the Auger line shape [1,2,3]. One can predict the rate of
excitations from each core orbital as a function of its angular momentum along a photon
polarization direction and/or along the Auger emission direction. This highlights aconnection between partial densities of states and resonant Auger spectra based on “core-holememory” that retains angular-momentum information. We illustrate this for a variety of x-ray
edges in several noble metals.

Fig. 1: Resonant Auger emission spectra for several photon energies given relative to threshold.

References[1] W. Drube, R. Treusch, and G. Materlik, Phys. Rev. Lett. 74, 42 (1995).
[2] A. Föhlisch, O. Karis, M. Weinelt, J. Hasselström, A. Nilsson, and N. Mårtensson, Phys. Rev. Lett. 88, 027601(2002).
[3] J.C. Woicik, E.L. Shirley, C. Weiland, A.K. Rumaiz, C.A. Cardot, J.J. Kas, and J.J. Rehr, Phys Rev. B 104,
245131 (2021).

1a2-2 : Contributed

Accurate and Non-destructive Layer Structure Analysis of
Semiconductor Materials Using Angle Resolved HAXPES
Hsun-Yun Chang1, Wei-Chun Lin2, Yu-Chun Huang3, Kazutoshi Mamiya1,
Shinichi Iida1
1
2

ULVAC-PHI, Inc, 2500 Hagisono, Chigasaki, Kanagawa, Japan

Department of photonics, National Sun Yat-sen University, Kaohsiung, Taiwan
3

Metal Industries Research & Development Centre, Kaohsiung, Taiwan

Optimizing the processes of semiconductor materials to increase the efficiency is always
one of top target in photovoltaic industries. Not only surface chemical analysis is essential toexamine the effect of processes to these semiconductor materials, but also the accurate layer
structure analysis is critical to inspect the quality of semiconductor devices. X-ray
photoelectron spectroscopy (XPS) is a common tool to reveal the surface chemical composition.
In addition, by performing the angle resolved XPS (AR-XPS), the layer structure of multiple
thin films can be obtained. When the total thickness of multilayer is over the detection depth,
hard X-ray photoelectron spectroscopy (HAXPES) holds the potential to perform AR-HAXPES
without the need of sputtering due to its greater detection depth. To compare the layer structure
analysis using AR-XPS and AR-HAXPES, Al2O3 with 15 nm thickness is deposited on c-Si
surface and the thickness of thermally grown SiO2 passivation layer is controlled by a series ofannealing temperature. To examine the thickness of interfacial SiO2 layer, a lab type XPS
system equipped with both A K and CrK X-ray sources are utilized to perform AR-XPS andAR-HAXPES respectively. Because the thickness of Al2O3 layer is over the detection depth ofAK

X-ray, sputtering using monoatomic Ar+ to remove a thickness of Al2O3 layer isperformed to obtain the signal from interfacial SiO2 layer and c-Si substrate. The result shows
the thickness of SiO2 layer increases with the annealing temperature in both AR-XPS and ARHAXPES. However, the SiO2 thickness of AR-XPS result is thinner than that of AR-HAXPES.
The reduction of SiO2 observed in AR-XPS spectrum suggests the thinner SiO2 layer is causedby sputter damage. The AR-HAXPES is performed without any sputtering and the obtained
thickness of SiO2 is found to be close to the cross-sectional TEM image. Therefore, with thegreater detection depth, AR-HAXPES realized the accurate thickness analysis of semiconductormaterials. In the presentation, the examples of AR-HAXPES for semiconductor materials will
be demonstrated.

1a2-3 : Contributed

Theoretical and experimental HARPES study of
Weyl-semimetal TaAs: The application of machine-learning
Trung-Phuc Vo1, Arian Arab2, Sunil Wilfred D'Souza1, Laurent Nicolaï1, Tien-Lin
Lee3, Nitesh Kumar4, Claudia Felser4, Alexander Gray2, and Ján Minár1
New Technologies - Research Centre, University of West Bohemia, 301 00 Pilsen, Czech
Republic2
Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
3
Diamond Light Source Ltd., Didcot, Oxfordshire OX11 0DE, United Kingdom
4
Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden,
Germany

1

A Weyl semimetal is a new matter state possessing Weyl fermions near the Fermi level withseveral unique physical properties and it is confirmed by the existence of Fermi arc surface states[1]. In this work we study tantalum arsenide (TaAs) which is a prototypical Weyl semimetalcompound. The electronic structure properties have been studied by soft and hard X-ray angleresolved photoemission spectroscopy (ARPES) at energies of 440 eV and 2150 eV, respectively.
For the first time, TaAs is experimentally investigated by the bulk sensitive photoemission in thehard X-ray regime. In order to interpret experimental data we performed one-step model ofphotoemission calculation which includes all matrix elements and final state effects [2-4]. Due tothe strong photon momentum effects and uncertainty in the tilt of experimental geometry weused a so-called machine learning algorithm combined with a free-electron final-state model tofind best possible experimental parameters. Our findings re-emphasize the overwhelming
accuracy of hard X-ray ARPES (HARPES) compared to the traditional ultraviolet and soft X-ray
one in case of bulk electronic structure, motivating further material discoveries [5].

References[1] S. Xu et al., Science 349, 6248 (2015).
[2] H. Ebert et al., Rep. Prog. Phys. 74, 96501 (2011).
[3] H. Ebert et al., The Munich SPR-KKR Package, version 7.7, http://olymp.cup.uni-muenchen.de/ak/ebert/SPRKKR (2017).
[4] J. Braun et al., Phys. Rep. 740, 1 (2018).
[5] A. X. Gray et al., Nat. Mater. 10, 759 (2011).

1a2-4 : Contributed

Core-level peaks and the inelastic background in HAXPES:a depth-resolved analysis of the CdS/Cu(In,Ga)Se2
interface for thin-film solar cells
Dirk Hauschild1,2,3, Ralph Steininger1, Dimitrios Hariskos4, Wolfram Witte4,
Sven Tougaard5, Clemens Heske1,2,3, and Lothar Weinhardt1,2,3
1
Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute ofTechnology (KIT), Hermann-v.-Helmholtz-Platz 1,76344 Eggenstein-Leopoldshafen,
Germany2

Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute ofTechnology (KIT), Engesserstr. 18/20, 76131 Karlsruhe, Germany

3

Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV),
4505 Maryland Parkway, Las Vegas, NV 89154-4003, USA
4

Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW),
Meitnerstr. 1, 70563 Stuttgart, Germany
5

Department of Physics, Chemistry and Pharmacy, University of Southern Denmark,Campusvej 55, DK-5230 Odense M, Denmark

Interfaces are crucial for multilayer-containing electronic devices (such as batteries or solar
cells), generally (only) optimized empirically. For a further insight-driven optimization, a
deeper understanding of the interface properties in such devices needs to be obtained. Hard xray photoelectron spectroscopy (HAXPES) is predestined to characterize (buried) interfaces,
as it is non-destructive, chemically sensitive, and the inelastic mean free path Ȝ of the(unscattered) photoelectrons can be tuned (e.g., up to ~16 nm for photon excitation energies
up to 15 keV). In addition, the inelastic background contains information about the elemental
distribution for depths of 10-Ȝ, even if the corresponding (unscattered) photoelectron peakis fully attenuated.
In this contribution, we analyze both the core-level peaks and the inelastic background of aseries of CdS/CIGSe interface samples [1]. This interface is the central component inchalcopyrite-based thin-film solar cells (with record efficiencies above 23% [2]). For thispurpose, HAXPES spectra with photon excitation energies from 2.1 up to 14 keV werecollected using the newly commissioned X-SPEC beamline at the KIT synchrotron [3]. We
paint a depth-resolved picture of the CdS/CIGSe interface, for which the solution-grown CdS
film thickness can be accurately determined as a function of the CdS deposition time. We alsofind that, for shorter CdS deposition times, the film thickness varies laterally. Furthermore,
small amounts of Se and process-related Rb can be detected in a thin (~2 nm) surface layer of
all investigated CdS films. The findings thus demonstrate the power of HAXPES to discern
details of a buried interface in applied materials systems and devices.
References[1] D. Hauschild et al., J. Vac. Sci. A 39, 063216 (2021)[2] M. Nakamura et al., IEEE J. of Photovolt. 9, 1863 (2019)[3] L. Weinhardt et al., J. Synchrotron Rad. 28, 609 (2021)

1p1-1 : Invited
HIGASHI, WINDER, KUNEŠ, and HARIKI

LDA+DMFT approach to core-level x-ray spectroscopies in
Supplemental Material [54], reveal that for optimal Δ
correlated electron
systems
doped holes
are almost equally shared by Ni, Nd, and O sites.
dp

The calcula
behavior to N

This is a remarkable difference to monovalent cuprates or1
divalent
NiO. In thesesystems of 1strong
charge-transfer
Atsushi Hariki1, Keisuke Higashi, Tatsuya
Yamaguchi,
character, the1 doped holes reside2
2 predominantly in O 2p
Winder Mathias , Takayukiorbitals,
Uozumi, Jan ofKuneš
irrespective
a substantial 3d spectral weight1

just below the Fermi level [60]. Moreover, for the optimal
Δdp valuesUniversity,
inferred above,the doped
holes
in NdNiO2
Department of Physics and Electronics, Osaka Prefecture
Sakai,
Osaka
599-8531,
Japando not enter the Ni 3z2 − r2 orbitals (Fig. 4). The single2
band
Hubbardthus, valid not only for theInstitute for Solid State Physics, TU
Wien,
1040description
Vienna,is,Austria

parent NdNiO2 but also for the superconducting one
Nd0.8 Sr0.2 NiO2 , as suggested by Refs. [35–37].
Proximity of NiO2 layers to a Mott state (precluded by
self-doping from Nd) suggests that a superexchange
We develop an ab-initio computational method for
simulatingcore-level
x-ray spectroscopies
interaction
still plays
a role despite
the metallic state.
the optimalΔdp , oxides
we arrive [1,2].
[54] at thenearestNi-Ni
in strongly correlated electron systems, such as 3dUsing
transition
metal
This
methodantiferromagnetic
exchangein the range
40–60 meV.
Givenbuilds on a combination of local density approximation(LDA) anddynamical
mean-field
theorythe oversimplification of representing spin response of a
(DMFT), which can be viewed as an extension of conventionalmodel,interactions,employedmetal in terms ofcluster
local moments
thiswidely
value isin HAXPES analysis, to incorporate the orbital hybridization
withtheconniuumofvalencebands
consistent with 69 meV inferred from the RIXS experimenta related compoundin the realstic lattice. This method is particulary on
beneficial
to studyLanonlocal
charge-transfer
4 Ni3 O8 [61].

screening features in core-level HAXPES spectraof a series of 3d, 4d, and 5d transition metal oxides[1,3,4]. Besides, it provides a coherent descriptionof HAXPES and other core-level x-ray excitation
processes, e.g., x-ray absorption spectroscopy andresonant inelastic x-ray scattering [2]. In this talk,a special focus is paid on the Ni 2p core-level xray photoemission spectra of NdNiO2, see figure, amother compound of recently discovered
superconducting infinite-layer nickelate. We showthat a future HAXPES experiment will allow toderive the key parameters of this material class [4].

(a)As expected
the experimen
peak correspo
2p3=2 to an emain peak is ahybridization w
Fig. 5(b) repro
however, the w
to draw concl
The RIXS
changes withall Δdp values
constant Eloss
Ein ) at Eloss ∼(Eloss linearly
from t2g → x2
reflects a rapid
ing Δdp , the R
upward shift t
Fig. 2(b)], whvicinity of thespectra with inpart, the onse

(a)

(b)

References[1] A. Hariki, T. Uozumi, and J. Kuneš, Phys. Rev. B 96, 045111 (2017).
[2] A. Hariki, M. Winder, T. Uozumi, and J. Kuneš, Phys. Rev. B 101, 115130 (2020).
[3] D. Takegami, C. Y. Kuo, K. Kasebayashi, J. G. Kim, C. F. Chang, C. E. Liu, C. N. Wu, D. Kasinathan, S. G.
Altendorf, K. Hoefer, F. Meneghin, A. Marino, Y. F. Liao, K. D. Tsuei, C. T. Chen, K.-T. Ko, A. Gunther, S. G.
Ebbinghaus, J. W. Seo, D. H. Lee, G. Ryu, A. C. Komarek, S. Sugano, Y. Shimakawa, A. Tanaka, T. Mizokawa, J.
Kuneš, L. H. Tjeng, and A. Hariki, Phys. Rev. X 12, 011017 (2022).
[4] K. Higashi, M. Winder, J. Kuneš, and A. Hariki, Phys. Rev. X 11, 041009 (2021).

FIG. 5. (a) Ni 2p3=2 XPS spectra and (b) Ni 2p3=2 XAS spectraof NdNiO2 calculated by the LDA þ DMFT method for different
Δdp values. The experimental data [9,12] are shown together. For
comparison, experimental Cu 2p3=2 XPS data of La2 CuO4 areshown (gray) [19]. The spectral broadening is taken into accountusing a Lorentzian 300 meV (HWHM) and a Gaussian 250 meV(HWHM) for XAS and a Lorentzian 500 meV and a Gaussian
400 meV for XPS. The XPS spectra with different broadening
widths can be found in Supplemental Material [54].

(b)FIG. 6. (a) Ni
of LaNiO2 calcu
Δdp values. The
Lorentzian 300(HWHM) for X
400 meV for X

041009-4

1p1-2 : Contributed

Theoretical prediction of core electron binding energies
using the ΔSCF method – applications to 3d transition metals
J. Matthias Kahk1, and Johannes Lischner 2
1

2

Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu, Estonia.
Department of Materials, and the Thomas Young Centre for Theory and Simulation ofMaterials, Imperial College London, London SW7 2AZ, United Kingdom.

Theoretical calculations of core electron binding energies are important for aiding theinterpretation of experimental core level X-ray photoelectron spectra. Previously, it has beenshown, that using the Δ-Self-Consistent-Field (ΔSCF) method, it is possible to predict accurate
absolute core electron binding energies in free molecules, adsorbed molecules, and periodic
solids [1,2]. However, so far, most theoretical work has focused on light elements (up to andincluding Cl), and relatively little is known about the performance of current theoretical methods
for heavier elements, including transition metals.
In this talk, a brief overview of the ΔSCF method will be given, and the requirements forpredicting accurate absolute core electron binding energies will be discussed. In addition, theapplication of the ΔSCF method to elements of the first transition metal series will be examined
in detail [3]. It is shown that scalar-relativistic ΔSCF calculations based on density functional
theory and the SCAN functional typically underestimate absolute transition metal (TM) 2p3/2 coreelectron binding energies in compounds of first row transition metals by ~ 0.5 – 1.0 eV.
However, calculated relative core electron binding energies (≈ binding energy shifts) are still
highly accurate, with a mean absolute error of 0.2 eV for a dataset of 60 compounds. Moreover,with the use of element-specific correction terms, the prediction of accurate absolute TM 2p3/2
core electron binding energies is also possible. Together with the recent work on extending the
ΔSCF method to periodic solids, these results lay the foundations for the use of ΔSCF
calculations for predicting core electron binding energies in a wide range of experimentally
relevant systems.
References[1] J.M. Kahk, and J. Lischner, Phys. Rev. Materials 3, 100801(R) (2019).
[2] J.M. Kahk, G.S. Michelitsch, R.J. Maurer, K. Reuter, and J. Lischner, J. Phys. Chem. Lett. 12, 9353 (2021)[3] J.M. Kahk and J. Lischner, arXiv preprint: arxiv.org/abs/2112.04200 (2021)

1p1-3 : Contributed

Time-resolved study of recoil-induced rotation by X-ray
pump - X-ray probe spectroscopy
Victor Kimberg 1,2
1

2

KTH Royal Institute of Technology, 10691 Stockholm, Sweden
IRC SQC, Siberian Federal University, 660041 Krasnoyarsk, Russia

Modern stationary X-ray spectroscopy is unable to resolve rotational structure. In the present
paper, we propose to use time-resolved two color X-ray pump-probe spectroscopy withpicosecond resolution for real-time monitoring of the rotational dynamics induced by the recoil
effect. The proposed technique consists of two-steps. The first short pump X-ray pulse ionizes
the valence electron, which transfers angular momentum to the molecule. The second timedelayed short probe X-ray pulse resonantly excites a 1s electron to the created valence hole. Dueto the recoil-induced angular momentum the molecule rotates and changes the orientation oftransition dipole moment of core-excitation with respect to the transition dipole moment of thevalence ionization, which results in a temporal modulation of the probe X-ray absorption asfunction of the delay time between the pulses. We developed an accurate theory of the X-raypump-probe spectroscopy of the recoil-induced rotation and study how the energy of thephotoelectron and thermal dephasing affect the structure of the time-dependent X-ray absorption
using the CO molecule as a case-study. We also discuss the feasibility of experimental
observation of our theoretical findings, opening new perspectives in studies of molecularrotational dynamics.

Fig. 1: Scheme of the electronic transitions (left panel) in the studied pump-probe process with two timedelayed X-ray pulses (right panel).

1p2-1 : Plenary

Hard X-ray Photoelectron Spectroscopy of Functional Oxide
Films and Heterointerfaces
Michael Sing
Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, JuliusMaximilians-Universität Würzburg, 97074 Würzburg, Germany

Hard X-ray photoelectron spectroscopy has now established itself as a useful method for the
study of a broad class of materials and is recognized not only by experts in the field. In my talk, I
will review our recent results on functional oxide films and heterointerfaces that may serve as aplatform for future all-oxide electronic devices. Topics include oxygen vacancy-driven bandengineering at the interface of LaAlO3/SrTiO3 heterostructures [1], band alignment and electronic
reconstruction in the LaVO3/SrTiO3 system [2], determination of the bulk spin polarization ofmagnetite [3], and momentum mapping of the buried high-mobility two-dimensional electron
system in LaAlO3/KTaO3 [4]. The latter two studies were performed using a time-of-flight
momentum microscope equipped with a spin-filter crystal.

Fig. 1: (a) Fermi surface map of the buried two-dimensional electron system in the LaAlO3/KTaO3
heterostructure. (b) Spin-resolved valence-band spectra of a Fe3O4(111) film, measured with an excitation
HQHUJ\RIKȞ NH9

References[1] J. Gabel, P. Scheiderer, M. Zapf, M. Stübinger, C. Schlueter, T.-L. Lee, M. Sing, and R. Claessen, to besubmitted.
[2] M. Stübinger, J. Gabel, P. Scheiderer, M. Zapf, M. Schmitt, P. Schütz, B. Leikert, J. Küspert, M. Kamp, P.K.
Thakur, T.-L. Lee, P. Potatov, A. Lubk, B. Büchner, M. Sing, and R. Claessen, Phys. Rev. B 103, 235128 (2021),
Editors' Suggestion.
[3] M. Schmitt, O. Kirilmaz, S. Chernov, S. Babenkov, D. Vasilyev, O. Fedchenko, K. Medjanik, Yu. Matveyev, A.
Gloskovskii, C. Schlueter, A. Winkelmann, L. Dudy, H.-J. Elmers, G. Schönhense, M. Sing, and R. Claessen,
Phys. Rev. B 104, 045129 (2021).
[4] M. Zapf, M. Schmitt, J. Gabel, P. Scheiderer, M. Stübinger, B. Leikert, G. Sangiovanni, L. Dudy, S. Chernov, S.
Babenkov, D. Vasilyev, O. Fedchenko, K. Medjanik, Yu. Matveyev, A. Gloskowski, C. Schlueter, T.-L. Lee, H.J. Elmers, G. Schönhense, M. Sing, and R. Claessen, arXiv:2110.15158.

1p2-2 : Contributed

Proximity-induced spin-orbit interaction in
MoSe2 overlayered with amorphous Pb films
Jan Minar1,x, Fatima Alarab2 , Vladimir Strocov2

1

New Technologies, Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Plzen,
Czech Republic
2

Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland

To design new functional materials for our increasing daily demands, we must abandon standard
models and move towards innovative compounds. These may be based on hybrid systems andheterostructures, invoking new physical mechanisms originating from proximity effects. Spinorbit (SO) proximity effects, in particular, are finding increasing applications across the whole
spectrum of condensed matter physics. The present work focuses on the modulation of the SO
interaction in 2H-MoSe2 which is induced by proximity effects at its interface with amorphousfilms of Pb, the high-Z element providing strong SO coupling. The key element of this researchstudy is the formation of amorphous Pb overlayers rather than epitaxial crystalline ones, allowing
us to overcome the k-space wavefunction mismatch at the interface. With an advantage of theenhanced probing depth, the use of soft x-ray angle-resolved photoelectron spectroscopy (SXARPES) allows reaching the interface regions where the SO interaction is modulated. k-spacedependence of the proximity-induced SO interaction, as well as its dependence on the Pboverlayer thickness will be presented. Experimental SX-ARPES data are combined withcorresponding state of the art fully relativistic one-step model calculations based on the mutiple
scattering Green function KKR method. The amorphous layer of Pb was simulated by thecoherent potential approximation. This fundamental knowledge will pave novel approaches
towards realization of spintronic devices.

1p2-3 : Contributed

Studying anisotropic electronic structure in 2D-layered
crystals using resonant Auger spectroscopy
Fredrik O.L. Johansson 1,2,*, Elin Berggren3, Rebecka Lindblad4, Olle Eriksson5,
Biplab Sanyal5, and Andreas Lindblad 1
1

Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, 4 place Jussieu,
F-75005, Paris, France
2
Division of Applied Physical Chemistry, Deptartment of Chemistry, KTH – Royal Institute ofTechnology, Teknikringen 30, SE-100 44 Stockholm, Sweden
3
Division of X-ray Photon Science, Department of Physics and Astronomy, Lägerhyddsvägen 1,
SE-75237 Uppsala4
Dept. of Chemistry, Ångström Laboratory, Uppsala University, Box 538 SE-751 21 Uppsala
5
Division of Materials Theory, Department of Physics and Astronomy, Uppsala University,
Box 516, SE-751 20 Uppsala, Sweden
Two-dimensional (2D) materials beyond graphene have shown promise in various applications,e.g., nanoelectronics and rechargeable batteries. One class of these materials is the transition metal
dichalcogenides (TMD) a family of layered materials weakly bonded through van der Waals forces.
The layered structure of these materials imply that its electronic properties are anisotropic in thelayers versus between the layers and this has been studied recently [1,2]. We have usedpolarization-dependent x-ray absorption in the tender x-ray regime at the S K edge and maps of theresonant Auger spectra in the S KLL Auger kinetic energy range to study the anisotropy in- versus
out of plane in SnS2, as seen in Fig. 1 [1]. A close sibling of SnS2 is SnS which also exhibits
anisotropic charge transfer in- versus out of plane [3]. Compared to SnS2 which is hexagonal, SnS
is orthorhombic and thus also exhibit intraplane anisotropy along the layers two primary directions,the zig-zag and armchair directions. We show that resonant Auger spectroscopy is a method that
we can achieve directional and orbital specificity with when studying in- and out of planecharacteristics of layered materials.
a)

b)

c)

In-planeOut-of-plane
52480
Photon Energy [eV]Photon Energy [eV]

2480
4

2475

3
1

2470

2465
2105

S0

1

D2

1

2110
2115
2120
Electron Kinetic Energy [eV]

4

2475

2465
2125

3
2
1

2470

2105

S0

1

D2

1

2110
2115
2120
Electron Kinetic Energy [eV]2125

Fig.1 a) shows the principle of using the polarization direction to excited electrons into specific orbital, b)
and c) shows the distinctly anisotropic resonant structure in- and out of plane of SnS2. Adapted from [1]References[1] F.O.L. Johansson et al. Phys. Rev. B 102, 035165 (2020)[2] C.N. Eads et al. Nature Commun. 8, 1369 (2017).
[3] F.E. Oropeza et al. J. Mater. Chem. C, 2021,9, 11859-11872

1p2-4 : Contributed

Dynamic SXPS and HAXPES study of the Thermal Stabilityof TixW1-x/Cu Heterostructures
Curran Kalha 1, Tien-Lin Lee 2, Pardeep K. Thakur 2, Michael Reisinger 3, Johannes
Zechner 3, Michael Nelhiebel 3 and Anna Regoutz 1
1 Department of Chemistry, University College London, 20 Gower Street, WC1H 0AJ, UK.
2 Diamond Light Source Ltd., Harwell Science & Innovation Campus, Oxford, OX11 3QR, UK.
3 Kompetenzzentrum Automobil- und Industrie-Elektronik GmbH, Europastraße 8, 9524 Villach,

Austria.

For power semiconductor devices, a binary alloy of titanium-tungsten (TixW1-x) is often used asa diffusion barrier to isolate the copper metallisation interconnects from the silicon substructure.
A diffusion barrier is necessary as Cu rapidly diffuses into Si at low temperatures (<200°C),
which can lead to premature device failure.[1] However, the progressive miniaturisation offeature sizes in microelectronic devices has increased the probability of higher local power
densities and temperatures. Exposure to such conditions has been shown to induce a segregationof Ti out of the TiW and an interdiffusion into the adjacent Cu metallisation. This loss of Ti canultimately lead to the degradation and failure of the diffusion barrier, and allow for the interaction
between Si and Cu.[2]Here, device-relevant Si/SiO2/TiW(300 nm/Cu(25 nm) thin film stacks were characterisedusing a combination of soft and hard X-ray photoelectron spectroscopy (SXPS and HAXPES) at
beamline I09 of the Diamond Light Source, using X-ray photon energies of 1.5 keV and 5.9 keV,
respectively. The combination of SXPS and HAXPES provides the opportunity to nondestructively probe across multiple depths, including the buried TiW/Cu interface and bulk TiW.
To study the thermal stability of TiW, two experiments were conducted. The first involved astatic measurement, where samples were ex-situ annealed for varying durations at 400°C under
an inert atmosphere to simulate temperature stress on the device stacks. SXPS/HAXPES
measurements were then conducted across the TiW/Cu interface. The second involved a dynamic
measurement, where the same as-deposited samples were annealed in-situ within the analysis
chamber of I09 to 400°C, and core level spectra were continuously measured to track theevolution of the Ti enrichment at the Cu surface during the annealing process.
During annealing, Ti was shown to segregate out of the TiW barrier and diffuse across Cu attemperatures as low as 250°C. However, the ex-situ interface measurements suggest that despite
the out-diffusion of Ti, the diffusion barrier remains functional at 400°C as no intermetallic
phases are observed and the downward diffusion of copper is successfully suppressed. Overall,the combined ex-situ and in-situ SXPS/HAXPES experiment systematic approach provides aclear picture of the influence of temperature and annealing duration as experience during device
manufacturing or operation, on the stability of the TiW film and TiW/Cu interface.
References[1] R. Sachdeva et al., Appl. Phys. Lett. 79, 2937 (2001)[2] C. Kalha et al., J. Appl. Phys. 129, 195302 (2021)

1p3-1 : Contributed

Probing q an m ma erial in erface i h HAXPES a he
GALAXIES beamline : re l and per pec i e
J.-P. Rueff1, A. Raji1,2, A. Gloter2 and M. Bibes3
1

S nchrotron SOLEIL, L Orme des Merisiers, BP 48 St Aubin, 91192 Gif sur Yvette, France
Laboratoire de Ph sique des Solides, CNRS, Universit Paris Sacla , 91405 Orsa , France
3
Unit Mi te de Ph sique CNRS, Thales, Universit Paris-Sacla , 91767 Palaiseau, France

2

The functionalit of novel quantum materials derives from the competition bet een the internal
degrees of freedom (electrons, spin, orbital, topolog , spin-orbit coupling) most notabl observed
at interfaces. An intense research activit has been set off for fabricating and manipulatinginterfacial properties of quantum materials leading to a fren of scientific discoveries including
2DEG, interfacial superconductivit , etc. HAXPES appears as a major probe of electronicinterfacial behavior due to its superior probing depth and sensitivit to the local atomic properties.
Here, e ill revie recent HAXPES results obtained at the GALAXIES beamline, SOLEIL
S nchrotron [1] regarding interfacial properties of metal o ides, including CMO / YCO
superlattices [2] speciall hen combined to standing ave approach. E tension of this ork toinvestigating materials properties in operando conditions or characteri ing ultrafast charge
d namics as recentl obtained in GeSe [3] ill be discussed. These results ill be put in theconte t of the 4th generation (DLSR) s nchrotron sources ith much reduced H source si e hichoffer ne possibilities for in-depth interfacial characteri ation.

. 1: () HAXPESaaa

GALAXIES a
SW-HAXPES (;()
R . [2])

Reference[1] J.-P. Rueff a ., J. S
[2] L. Cambou a ., J. Va[3] Z. Chen a ., NaC

Ra . 22, 175 (2015).
S&T
A 39, no. 5, 053204 (2021)aP
4, no. 1, 138 (2021).

CMO / YCO

1p3-2 : Contributed

CaCu3Ru4O12: a high Kondo-temperaturetransition metal oxide
Daisuke Takegami1, Chang-Yang Kuo1, 2, Keito Kasebayashi3, Jeong-Gyu Kim4,
Chun-Fu Chang1, Cheng-En Liu1, 5, Chi-Nan Wu1, 6, Deepa Kasinathan1, Simone G.
Altendorf1, Katharina Hoefer1, Federico Meneghin1, Andrea Marino1, Yen-Fa
Liao2, Ku-Ding Tsuei2, Chien-Te Chen2, Kyung-Tae Ko4, Axel Günther7, Stefan G.
Ebbinghaus8, Junwon Seo1, Dong-Hoon Lee1, Gihun Ryu1, Alexander C.
Komarek1, Satoshi Sugano9, Yuichi Shimakawa9, Arata Tanaka10, T. Mizokawa11,
Jan Kuneš12, Liu Hao Tjeng1, and Atsushi Hariki3, 12
1

Max Planck Institute Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany
National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, 30076 Hsinchu, Taiwan
3
Department of Physics and Electronics, Osaka Prefecture University 1-1 Gakuen-cho, Nakaku,
Sakai, Osaka 599-8531, Japan2

4

Department of Physics, POSTECH, Pohang 37673, Korea
Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan
6Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
7
Experimental Physics V, University of Augsburg, 86135 Augsburg, Germany
8
Institute of Chemistry, Martin Luther University Halle-Wittenberg, 06120 Halle, Germany
9Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan10
Department of Quantum Matter, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
11
Department of Applied Physics, Waseda University, Shinjuku, Tokyo 169-8555, Japan
12
Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
5

We present a comprehensive study of CaCu3Ru4O12 using bulk sensitive hard and soft x-ray
spectroscopy combined with local-density approximation (LDA) + dynamical mean-field theory(DMFT) calculations. Correlation effects on both the Cu and Ru ions can be observed. From theCu 2p core level spectra we deduce the presence of magnetic Cu2+ ions hybridized with areservoir of itinerant electrons. The strong photon energy dependence of the valence band allows
us to disentangle the Ru, Cu, and O contributions and thus to optimize the DMFT calculations.
The calculated spin and charge susceptibilities show that the transition metal oxide CaCu3Ru4O12
must be classified as a Kondo system and that the Kondo temperature is in the range of 500-1000
K. The high Kondo temperature is the key to reconcile the contradictory conclusions of theexisting studies (conducted at moderate temperatures) on this material. Our work [1] brings defacto the Kondo physics from 4f/5f intermetallic systems to also transition metal oxides. The
perovskite material class with the ACu3B4O12 structure provides a new platform for integratingcompeting quantum phenomena in strongly correlated electron systems.
References[1] D. Takegami et al., Phys. Rev. X, (accepted 2021).

1p3-3 : Contributed

Lab-scale Hard X-ray Photoelectron Spectroscopy for the
analysis of buried interfaces in device technologies
Pierre-Marie Deleuze1, Eugénie Martinez 1, Kateryna Artyushkova 2, and Olivier
Renault1
1

2

Univ. Grenoble-Alpes, CEA, Leti, 38000 Grenoble, France.
Physical Electronics Inc., 18725 Lake Drive E, Chanhassen, MN 55317, USA.

Photoelectron spectroscopy plays a key role in the characterization of surfaces and interfaces
which
is
of
primaryimportance
in
the
field
of
devicetechnology.
However instruments traditionally available in the lab are usually equipped with Al KD
radiation (1486.6 eV), which limits the probing depth and therefore prevents from analyzing
buried interfaces deeper than a few nanometers without resorting to destructive methods
such as sputtering, causing strong chemical modifications.
However, in many modern technologies, the interfaces of interest are most of the time deeply
buried underneath metal electrodes or oxides layers, requiring deeper analysis. This canbe achieved by using higher energy photons. Hard x-ray photoelectron spectroscopy(HAXPES) have long been available at synchrotron facilities but its limited access lessen
its interest as process development requires routine measurements and high reactivity. The
recent advent of commercial lab-scale instruments opens new possibilities for nondestructive buried interface analysis [1-2].
In this presentation, we present the possibilities offered by a novel Cr KD (5414.8 eV)
lab-scale HAXPES instrument (Quantes, Physical Electronics Inc.). The first part is devoted
to the chemical analysis of buried interfaces in TiN/HfO2 stacks intended for oxide-resistive
random access memories (OxRAMs). The influence of a metallic Ti layer deposited at theinterface is especially examined. Results reveal that the addition of a Ti layer promotes the
reduction of hafnium oxide thus creating oxygen vacancies, which in turn greatly
determine the device properties. The second part focuses on quantitative aspects on thisnew instrument and in particular describes an approach to determine relative sensitivity
factors. The accuracy of the empirically derived sensitivity factors is confirmed by thequantitative analysis of binary and ternary compounds.
Acknowledgements:
This work was performed at the Platform For NanoCharacterization (PFNC) of
CEA-Grenoble with support of the Recherche Technologique de Base program of French
National Research Agency (ANR).
References[1] Renault O, et al. Surf. Interface Anal. 2018,50:1158-1162[2] Siol S, et al. Surf Interface Anal. 2020; 52: 802– 81

1p3-4 : Contributed

Metallic Antiferromagnetic Spintronics: Mn2Au a case study
Sunil Wilfred DSouza1, Hans-Joachim Elmers2, Satya Prakash Bommanaboyena2,
Vladimir N. Strocov3, Martin Jourdan2 and Jan Minár1
1

New Technologies Research Centre, University of West Bohemia, Univerzitní 8, CZ-306 14
Pilsen, Czech Republic.
2
Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz,
Germany.
3

Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland

The electronic structure of bulk Mn2Au has been investigated by first-principles densityfunctional theory calculations based on the Green’s function technique. Existence of significant
out-of-plane magnetic anisotropy combined with the large strength of short range
antiferromagnetic exchange interactions between Mn atoms located at two dfiferent Wyckoff
positions results in the stabilization of the antiferromagnetic ground state. Two dimensional plotsof constant energy surfaces in the Γ-X-Σ plane of the Brillouin zone exibits a 4-fold to 2-foldsymmetry breaking as a function of the binding energy at 0.00 eV and 0.25 eV below the Fermi
surface. We find that such a symmetry breaking in Mn 2Au is arising due to the degeneartion of
the electronic bands in the presence of external magnetic field indicating a strong spin-orbit
coupling interaction. Our results describes the tuning of the magnetic and electronic properties of
Mn2Au for spintronic applications.

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References[1] H. J. Elmers et al., ACS Nano 14, 17554–17564 (2020).

1n1-1 : Invited

Materials Research for Metal-Halide Perovskite Solar Cells
Enabled by Hard X-ray Photoelectron Spectroscopy
Marcus Bär1,2,3,4
1

Dept. Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB),
Albert-Einstein-Str. 15, 12489 Berlin, Germany
2

Energy Materials In-situ Laboratory Berlin (EMIL), HZB, Albert-Einstein-Str. 15, 12489 Berlin,
Germany3Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy (HI ERN), Albert-Einstein-Str.
15, 12489 Berlin, Germany
4

Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg(FAU), Egerlandstr. 3, 91058 Erlangen, Germany

The multitude of layers, interfaces, elements, impurities, defects, etc. contributing to the structure,function, and performance of solar cells means that characterization and fundamental
understanding of the chemical and electronic structures of each component, as well as theirinteractions at interfaces – also upon external stimuli – are crucial to support technical progress.
HAXPES can reveal crucial information and enable studies that would not be possible employing
soft X-rays, opening new routes to insight-driven strategies to improve device performance.
To showcase the capabilities, I will present HAXPES-derived chemical and electronic structure
information of the (currently) most prominent absorber material for solar cells: Metal-halide
perovskites – corresponding devices have impressed by an unprecedented performance increaseover the past decade and are now on the verge of revolutionizing commercial PV. The
presentation will include some examples focussing on near-surface bulk and interface
characteristics and how these properties are influenced by illumination, bias application, or
exposure to humidity.

1n1-2 : Contributed

Characterization of Ferroelectric Devices:
HfZrO thin films on InAs
Austin Irish 1,3, Andrea Troian2,3,4, Yen-Po Liu1,3, Robin Athle2,3, Rohit Yadav1,3,
Lars-Erik Wernersson2,3, Mattias Borg2,3 and Rainer Timm 1,3
1

2

Synchrotron Radiation Research, Lund University, Sweden
Electrical and Information Technology, Lund University, Sweden
3
NanoLund, Lund University, Sweden
4
MAX IV, Lund, Sweden

High-k hafnium oxides such as HfZrO have amassed interest due to their dielectric superiority
over silicon. Compatible with atomic layer deposition, exploitation of their ferroelectricity
promises thin film memory technologies which are poised to invigorate electronics. Sophisticatedcontrol and characterization remain vital as structural size and complexity are pushed to theirnanometric limits. Exploiting the brilliance of synchrotron-based hard x-ray photoelectron andabsorption spectroscopies, we get a deep and realistic look inside next-generation memories.
After thorough ex-situ analysis, we push further with operando studies for insight into actual
device functioning and performance. The result is unparalleled access to the origin and innerworkings (ex. wake-up, switching and endurance) of hafnia-based ferroelectricity.

Fig. 1: Angle-resolved hard X-ray photoelectron spectroscopy is able to penetration functioning devicematerial stacks more than ten nanometers thick. Looking through the top electrode and the ferroelectric
dielectric, we probe the bottom high-k/III-V interface and monitor operando chemical changes.

1n1-3 : Contributed

Combining depth-sensitive X-ray spectroscopic andscattering techniques to probe interfacial magnetic
phenomena in oxide superlattices
Jay R. Paudel1, Michael Terilli 2, Ivana Vobornik3, Pasquale Orgiani3, Giancarlo
Panaccione3, Christoph Klewe4, Padraic Shafer4, Vladimir Strocov5, Andrei
Gloskovskii6, Christoph Schlueter6, Jak Chakhalian2 and Alexander X. Gray1
1

Department of Physics, Temple University, Philadelphia, PA 19122, USA
Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
3
CNR-IOM, TASC Laboratory, Trieste, 34139, Italy
4
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
5
Swiss Light Source, Paul Scherrer Institute, Villigen, CH-5232, Switzerland
6
Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
2

Emergent interfacial ferromagnetism in CaMnO3/CaRuO3 and CaMnO3/LaNiO3 heterostructures
has been investigated for nearly two decades. Several experimental and theoretical studies suggestthat this phenomenon is stabilized by the charge transfer across the interface and suggest different
thicknesses of the resultant ferromagnetic layers [1-4]. In this comprehensive study [5], we have
utilized bulk-sensitive hard x-ray photoemission spectroscopy (HAXPES) and soft x-ray standingwave photoemission spectroscopy in both first- and second-order Bragg geometries to probe thedepth-dependent chemical profile and interfacial charge reconstruction in CaMnO3. Furthermore,
we have carried out polarization-dependent x-ray absorption spectroscopy and x-ray resonant
magnetic scattering to probe depth-resolved magnetic profile at the interfaces in these material
systems. Finally, high-resolution angle-resolved photoemission spectroscopy with in-situ pulsedlaser deposition synthesis were used to track the topology of the Fermi surface of LaNiO3 in the
superlattice across the thickness-dependent metal-insulator transition. The results were comparedto the first-principles theoretical calculations.
This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic
Energy Sciences, Materials Sciences, and Engineering Division under Award DE-SC0019297
References[1] Chandrasena, R. U. et al., Phys. Rev. B 98, 155103 (2018).
[2] Flint, C.L. et al., Phys. Rev. Mater. 1, 024404 (2017).
[3] Nanda, B. R. K. et al., Phys. Rev. Lett. 98, 216804 (2007).
[4] Takahashi, K.S. et al., Appl. Phys. Lett. 79, 1324 (2001).
[5] Paudel, J.R. et. al., in preparation (2022).

2a1-1 : Invited

Using X-ray optical effects in photoelectron spectroscopy to
study heterogeneous systems
1

S. Nemsak1
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

Due to its relatively large information depth, HAXPES has become a popular technique tostudy chemical and electronic properties of bulk materials and buried interfaces. By using X-ray
optical effects in near total reflection or in Bragg geometry (related to periodic samples, such as
multilayer mirrors), one can also achieve high depth selectivity. A few recent mini reviews werededicated to high resolution profiling of emergent phenomena at interfaces of complex oxidematerials [1,2], and high temperature applications [3]. In this talk, I will briefly introduce the Xray optical effects in play and give an overview of the standing-wave photoelectron spectroscopyof multilayer samples. Later I will discuss applications to a hybrid multiferroic system
BFO/LSMO [4] and extreme UV lithography photoresists [5,6].

Fig. 1: Schematics showing the formation of the X-ray standing wave over a reflective sample. Θinc is
incident angle of X-rays, λ is the wavelength, and Dsw is a standing wave period. Nodes and antinodes ofthe standing wave are present in planes parallel to the reflective surface.

References[1] C.-T. Kuo, G. Conti, J.E. Rault, C.M. Schneider, S. Nemšák, A.X. Gray, J. Vac. Sci. Tech. A 40, 020801 (2022).
[2] J.E. Rault, C.-T. Kuo, H.P. Martins, G. Conti, S. Nemšák, J. Vac. Sci. Tech. A 39, 060802 (2021).
[3] O. Karslıoğlu, L. Trotochaud, F. Salmassi, E.M. Gullikson, A. Shavorskiy, S. Nemšák, H. Bluhm, J. Vac. Sci.
Tech. A 40, 01327 (2022).
[4] H.P. Martins, S.A. Khan, G. Conti, A.A. Greer, A.Y. Saw, G.K. Palsson, M. Huijben, K. Kobayashi, S. Ueda,
C.M. Schneider, I.M. Vishik, J. Minár, A.X. Gray, C.S. Fadley, S. Nemšák, arXiv:2012.07993[5] G. Conti, H.P. Martins, I.A. Cordova, J. Ma, R.J. Wojtecki, P. Naulleau, S. Nemšák, J. Micro/Nanopatt., Mat.,and Metrology 20, 034603 (2021).
[6] H. P. Martins, G. Conti, I. Cordova, L. Falling, H. Kersell, F. Salmassi, E. Gullikson, I. Vishik, C. Baeumer, P.
Naulleau, C.M. Schneider, S. Nemsak, J. Phys. D: Appl. Phys. 54, 464002 (2021).

2a1-2 : Invited

New Diemensions of HAXPES: Variable Polarization,
Total Reflection, and Spin Resolution
Shigenori Ueda
National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan

Hard X-ray photoemission spectroscopy (HAXPES) with variable X-ray polarization is useful
tool for studying the bulk-sensitive electronic states of solids. Particularly, by utilizing the X-ray
polarization-dependent photoionization cross-sections in the valence electrons, one can probe
atomic orbital dependent electronic structures by X-ray polarization-dependent HAXPES [1].
We briefly show how the X-ray polarization affects the valence band HAXPES spectral shapes of
3d, 4d, and 5d transition metals [1-3]. The tendency of photoionization cross-section in the 3d,
4d, and 5d transition metals helps ones to understand the valence band spectra of multinary
compounds [1-3]. Since HAXPES is a bulk-sensitive probe of electronic states due to the large
inelastic mean-free-path of photoelectrons, it is used to detect the electronic states of not only
bulk but also buried interfaces [4]. To enhance the sensitivity to buried interfaces, take-off angle
dependent HAXPES measurements are generally performed. Instead of take-off angle dependent
HAXPES, we will show a method for probing the buried interface and bulk electronic structuresof magnetic thin films under MgO or AlOx layers obtained by HAXPES combined with X-ray
total reflection [5]. We will also present the result of spin-resolved valence band HAXPES
spectra for buried Fe films obtained by using an ultracompact Mott-type spin filter [6]. This spin
filter can be mounted on a sample carrier, and would be compatible with most HAXPES
apparatuses without modifying an electron analyzer [6]. Although the angle-resolved PES forband dispersion measurements is difficult to perform with hard X-rays, spin-resolved HAXPES,
which gives Brillouin-zone (or momentum) averaged information due to a low Debye-Waller
factor in HAXPES, can be a powerful tool for studying bulk-derived spin-dependent electronic
states of magnetically ordered materials.

References[1] S. Ueda and I. Hamada, J. Phys. Soc. Jpn. 86, 124706 (2017).
[2] S. Ueda and I. Hamada, J. Phys. Soc. Jpn. 90, 034706 (2021).
[3] S. Ueda and I. Hamada, J. Phys. Soc. Jpn. 91, 024801 (2022).
[4] S. Ueda, M. Mizuguchi, M. Tsujikawa, and M. Shirai, Sci. Technol. Adv. Mater. 20, 796 (2019).
[5] S. Ueda, Appl. Phys. Express 11, 105701 (2018).
[6] S. Ueda and Y. Sakuraba, Sci. Technol. Adv. Mater. 22, 317 (2021).

2a1-3 : Contributed

Gap States at SiO2/4H-SiC interface obtained from
Oprando Hard X-ray Photoelectron Spectroscopy
Yoshiyuki Yamashita1,2, Efi Dwi Indari 1, and Ryu Hasunuma 3
12

National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
Faculty of Engineering, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
3
University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan

SiC is attracting a great attention for high temperature, high frequency, and high voltage
operation power devices. Although SiC has a great advantage for the preparation of MOS
structures, one of big issues on SiC is the formation of high density of gap states at SiO2/SiC
interface. This causes a poorer channel mobility than predicted. Therefore, control of the gap
states is crucial for fabrication of the high quality SiC based MOS devises. However, the gap
states densities are usually below 0.1% interface atomic density, which hardly ever detect them
directly. Recently, we developed a new spectroscopic method to observe the energy distributionof gap states. This method is based on operando hard x-ray photoelectron spectroscopy (OPHAXPES). In the present study, we investigated the energy distribution of the gap states at the
SiO2/4H-SiC(0001) interface using OP-HAXPES.
The OP-HAXPES measurements were performed using BL15XU in SPring-8. An incident
photon energy was 5.95 keV while a total energy resolution was set to 240 meV.
The binding energy of the SiC substrate in Si 1s was shifted by applying a bias voltage between
top electrode and rear of the SiC substrate. These shifts were attributed to electron occupationand electron vacancy in the gap states at SiO2/4H-SiC(0001) interface. Therefore, analysis ofthese core-level shifts as a function of bias voltage enables us to obtain the energy distribution of
the gap states at SiO2/4H-SiC(0001) interface, which is shown in Fig. 1. For the gap states,
continuous states in the whole gap and the state with the discreate energy level near the CBM areobserved. The detail discussions will be performed in the conference.

Fig. 1: Energy distribution of the gap states at SiO2/4H-SiC(0001) interface.

2a1-4 : Contributed

X-SPEC: A 70 eV to 15 keV undulator beamline forelectron and x-ray spectroscopies
Lothar Weinhardt1,2,3, Ralph Steininger1, Dagmar Kreikemeyer-Lorenzo1, Stefan
Mangold1, Dirk Hauschild1,2,3, David Batchelor1, Thomas Spangenberg1, andClemens Heske1,2,3
1
Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute ofTechnology (KIT), Hermann-v.-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, 76344,
Germany23Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute ofTechnology (KIT), Engesserstr. 18/20, Karlsruhe, 76128, Germany

Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), 4505
Maryland Parkway, Las Vegas, NV, 89154-4003, United States

Electron and x-ray spectroscopies are highly valuable techniques for material characterization,
both in fundamental and applied studies. Applied material systems highly profit from a
combination of several of these techniques, offering different information depths withcomplementary information content. In particular, x-ray emission spectroscopy (XES),
resonant inelastic x-ray scattering (RIXS), and hard x-ray photoelectron spectroscopy(HAXPES) have seen a significant development over the last years and create a unique method
combination.
In this contribution, we report on the X-SPEC beamline [1], which was recently built,
commissioned, and is now operated at the KIT light source. X-SPEC is a high-flux
spectroscopy beamline for electron and x-ray spectroscopy, featuring a uniquely wide photon
energy range. Using a combination of soft and hard x-ray undulator sources and optics, XSPEC can cover an energy range from 70 eV up to 15 keV. The flux of the beamline ismaximized by optimizing the magnetic design of the undulator, minimizing the number of
optical elements, and optimizing their parameters.
The beam can be focused into two experimental stations that are designed for measuringsolid samples under UHV conditions, as well as for in situ and operando studies under ambientconditions, respectively. Measurement techniques include x-ray absorption spectroscopy(XAS), extended x-ray absorption fine structure (EXAFS), low-energy photoelectron
spectroscopy (PES) and HAXPES, as well as XES and RIXS. The wide energy range of thebeamline enables us to combine very surface-sensitive synchrotron PES measurements, using
electron energies at the minimum of the inelastic mean free path, with more bulk-sensitive
HAXPES at energies up to 15 keV.
We will discuss the design considerations and the resulting beamline layout, describe theperformance of the beamline, and show first spectroscopic results.
References[1] L. Weinhardt, R. Steininger, D. Kreikemeyer-Lorenzo, S. Mangold, D. Hauschild, D. Batchelor, T.
Spangenberg, and C. Heske, J. Synchrotron Rad. 28, 609 (2021).

2a1-5 : Invited

Upgrade of a HAXPES beamline BL09XU of SPring-8
Akira Yasui1, Yasumasa Takagi1, Taito Osaka2, Michihiro Sugahara2,
Naomi Kawamura1, Yasunori Senba1,2, Hiroshi Yamazaki1,2, Takahisa Koyama1,2,
Hirokatsu Yumoto1,2, Haruhiko Ohashi1,2, Kyo Nakajima1,2, Koji Motomura2,
Kenji Tamasaku1,2, Yusuke Tamenori1, and Makina Yabashi1,21Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
2
RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan

SPring-8 is conducting extensive upgrades of beamlines so as to introduce novel scientificcapabilities and to reinforce key functions as a research infrastructure. In 2021, an X-ray
undulator beamline BL09XU, which had been used for hard X-ray photoelectron spectroscopy(HAXPES) and nuclear resonant scattering (NRS) applications, was converted to a beamline
dedicated for HAXPES with merging the relevant activities at BL47XU. The key points of the
upgrade are summarized as follows [1]:1) Two types of analyzers, high-voltage-resistance (up to 12 kV) and wide-acceptance-angle(±32°) analyzers, are installed for the experimental hutch (EH) 1 and 2, respectively.
2) Different types of high-resolution X-ray monochromators (HRMs), as well as double phaseretarders for polarization control, are installed into the optics hutch (OH). A high tunabilityof the X-ray beam performance over a wide photon energy range is achieved.
3) A Wolter focusing mirror is installed in EH1 so as to provide a brilliant micron-sized X-ray
beam with high stability and reproducibility.
4) It is planned that a nano focusing device will be installed for EH2 for conducting nano
HAXPES analysis.
One of the specific targets at BL09XU is the resonant HAXPES analyses that we recently
developed. In the conventional HAXPES, the photon energies are fixed at discrete values, i.e., 6,
8, and 10 keV, by using high-resolution post–monochromator of Si 333, 444, and 555,
respectively, with a fixed Bragg angle. In the resonant HAXPES, however, we have made theincident photon energy sweeping available around an absorption edge of a specific element,
providing unique opportunities for extracting bulk electronic states associated with specificelements and orbitals. The upgraded beamline will expand the applicable targets of resonant
HAXPES from fundamental physics research to applied materials development, such as studies ofphotocatalytic, steel, and spintronic materials.
In this presentation, I will show the beamline characteristics, the commissioning results, andexamples of pilot experiments.

References[1] http://www.spring8.or.jp/wkg/BL09XU/instrument/lang-en/INS-0000000302/instrument_summary_view.

2p1-1 : Invited

Atomic Inner-Shell Resonance, Threshold, and Double
Ionization Studies
Stephen H. Southworth
Argonne National Laboratory
Bldg. 401, 9700 S. Cass Ave.,
Lemont, Illinois 60439 USA

We are using high-resolution electron spectroscopy and hard x rays for studies of atomic
inner-shell photoelectron and Auger electron dynamics. In experiments at the Advanced
Photon Source (APS), we studied L-shell Auger electron generation across the Kr K-edge at
14327 eV. Kr 1s hole states have high (64%) radiative decay probabilities. We recorded the1611-eV L2-M4,5N2,3 Auger line as x-ray absorption excites the Kr 1s-np Rydberg series
below threshold and the 1s continuum above threshold. The Auger line is only weakly
generated by direct L2 photoionization and strongly enhanced by K-L2 x-ray emission.
Consequently, the yield of the L2 Auger line follows the K-edge absorption cross section,
including the 1s-np Rydberg series, resulting in resonant Auger lines. Above threshold,energy shifts of the Auger line result from post-collision-interaction (PCI) with 1s
photoelectrons. Due to the 2p-1s fluorescence time delay [1], modeling PCI requires
combining the 0.24-fs 1s lifetime with the 0.50-fs 2p1/2 lifetime.
Double photoionization of He is a dynamical process driven by electron correlation. It has
motivated theory and experiments on heavier atoms that use K-2 hypersatellites in x-ray
emission and Auger electron spectra to determine KK/K cross-section ratios [2,3]. Using
high-resolution electron spectroscopy and 2.3-keV x rays at the GALAXIES beam line of
SOLEIL, Goldsztejn et al. recorded rich structure in the Auger electron spectrum of Ne
resulting from K-2V and K-1L-1V shakeup states as well as K-2 hypersatellites [4]. In order todetermine how the electron correlation states and the KK/K ratio varies with x-ray energy, werecorded the high-resolution Auger electron spectrum of Ne at several energies over 2.3-6.5
keV at the GALAXIES beam line. Using an identical electron spectrometer at the APS, we
extended the Ne measurements to 8.5 keV. Our goals for this study are to determine how theK-1L-1V and K-2 probabilities vary with x-ray energy both experimentally and in comparison
with theory.
This work was supported by the US Department of Energy, Office of Science, Basic Energy
Sciences, Chemical Sciences, Geosciences, and Bioscience Division
References[1] S. Kosugi et al., Phys. Rev. Lett. 124, 183001 (2020).
[2] T. Schneider et al., Phys. Rev. Lett. 89, 073002 (2002).
[3] J. Hoszowska et al., Phys. Rev. Lett. 102, 073006 (2009).
[4] G. Goldsztejn et al., Phys. Rev. Lett. 117, 133001 (2016); Phys. Rev. A 96, 012513 (2017).

2p1-2 : Contributed

First HAXPES results on clusters: K-shell photoexcitationand subsequent electronic decays in Ar clusters
Minna Patanen1, Eetu Pelimanni1, Andreas Hans2, Denis Céolin3, Iyas Ismail4,
Tatiana Marchenko3,4, Oksana Travnikova3,4, Maria Novella Piancastelli5, Samuli
Urpelainen1, Marko Huttula1, Ralph Püttner6, Marc Simon3,4
1

Nano and Molecular Systems Research Unit, Faculty of Science, P. O. Box 3000, 90014
University of Oulu, Finland
2

3

S nch

4

5

Universität Kassel, Institut für Physik und CINSaT, Heinrich-Plett-Straße 40, 34132
Kassel, Germanyn SOLEIL, L O me de Me i ie Sain -Aubin, BP 48, 91192 Gif-sur-Yvette Cedex,
FranceSorbonne Université, CNRS, Laboratoire de Chimie Physique-Matière et Rayonnement, 75005
Paris Cedex 05, France

Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala,Sweden6

Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

The access to the hard X-ray regime has opened new avenues in atomic and molecular physics[1], and HAXPES has brought new insights for studies of liquid and solid materials [2]. Whilethese fields are now well-established, after pioneering photoabsorption studies already in early90 b R h et al. [3], gas-phase clusters have been an uncharted territory in the landscape of
HAXPES research. Clusters are small atomic or molecular aggregates, which bridge the gap
between isolated species and condensed phase. We report here a study of K-shell excitation (~3.2
keV) and subsequent Auger decays in Ar clusters. The experiment was performed at GALAXIES
beamline (Synchrotron SOLEIL, Saint Aubin, France) [4]. The clusters were formed via adiabatice 8 ba ) h gh a 25
ei
e e a ure leading to
expansion of Ar (bac i g emean size of about 30 atoms per cluster. The high photon flux and high-resolution electron
analyser allowed us to record 2D maps in the region of the Ar 1s resonances, following evolutionof KLL, KLM, and LMM Auger spectra across the resonances to the region dominated by
EXAFS oscillations. Reference measurements for atomic Ar facilitated disentangling collective
and environment induced effects appearing in Ar clusters. These experiments serve as a starting
point for investigations of different types of clusters (e.g. hydrated species, core-shell clusters)
bringing important insight for e.g. fundamental charge transfer processes.
References[1] M. N. Piancastelli et al., Rep. Prog. Phys. 83, 016401 (2019).
[2] C. Kalha et al. J. Phys.: Condens. Matter 33, 233001 (2021).
[3] E. Rühl et al. J. Chem. Phys. 98, 6820 (1993).
[4] D. Céolin et al. J. Electr. Spectr. Rel. Phenom. 190, 188-192 (2013).

2p1-3 : Contributed

Translational and Rotational Recoil Effects In HAXPES ofFree Molecules
Faris Gelmukhanov 1,2
1

2

KTH Royal Institute of Technology, 10691 Stockholm, Sweden
IRC SQC, Siberian Federal University, 660041 Krasnoyarsk, Russia

The translational and rotational recoil effects together with related Doppler effect in X-ray
spectroscopy being natural fingerprint of nuclear motion gives deep insight in molecular nuclear
dynamics in bound and dissociative states [1]. The Doppler labeling of the fragments of the
dissociation together with the frequency controlled duration of X-ray scattering provides direct
and detailed information about the potentials and dynamics in repulsive states. The rotational
Doppler effect [1] in X-ray ionization gives site selective information about the valencemolecular orbitals[1]. The Doppler splitting of X-ray resonances [1] gives also an inique tool tostudy the nonequibrium distributions over translational and rotational degrees of freedom. The
Doppler control of the amount of which path information allowed us recently to attack the
background problem of the wave particle duality in Einstein-Bohr recoiling double-slit gedanken
experiment [1,2]. We demontrate at first time the dynamical rotational Doppler effect in highenergy Auger spectra of CO and show the quantum correlation of rotational and translational
degrees of freedom [1,3]. This was performed by hard X-ray C1s ionization of carbon monoxide
accompanied by spinning up the molecule via the recoil “kick” of the emitted fast photoelectron.
To visualize the molecular rotation, we use the dynamical rotational Doppler effect and an X-ray“pump- probe” device offered by nature itself. The time information in our experiment [8]originates from the natural delay between the C1s photoionization initiating the rotation and theejection of the Auger electron. We overview here our recent results devoted to the role oftranslational and rotational recoil effects on nuclear dynamics of molecules and clusters in hard
X-ray region (>10 keV) including recoil-induced dissociation [1,4]. We also overview our recent
results in direct time-resolved studies of the recoil-induced rotation.
References[1] F. Gel’mukhanov, M. Odelius, S. P. Polyutov, A. Föhlisch, and V. Kimberg, Rev. Mod. Phys. 93, 035001 (2021).
[2] X.J. Liu, Q. Miao, F. Gel’mukhanov, M. Patanen, O. Travnikova, C. Nicolas, H. Ågren, K. Ueda, and C. Miron,
Nature Photonics 9, 4120 (2015).
[3] D. Ceolin, J.-C. Liu, V. Vaz da Cruz, H. Ågren, J. Pascal Rueff, R. Puttner, T. Marchenko, R. Guillemin, R.
Kushawaha, L. Journel, M.N. Piancastelli, M. Simon, and F. Gel’mukhanov, Proc. Natl. Acad. Sci. USA 116, 4877
(2019).
[4] J.-C. Liu, V. V. da Cruz, S. Polyutov, A. Föhlisch, and F. Gel'mukhanov, Phys. Rev. A 100, 053408 (2019).

2p1-4 : Plenary

Gas phase HAXPES studies
Marc SIMON 1
1

CNRS & Sorbonne University, LCPMR, 4 place Jussieu, 75005 Paris, France

Gas phase HAXPES is a technic receiving a growing interest. The first results (see ref. 1 for a
recent review) have been obtained at SOLEIL between 2.3 and 13 keV of photon energy. This
technic has been successfully developed at Spring8 (Japan) [2] and APS (US) (see invited talk of
Stephen SOUTHWORTH) taking advantage of the scientific opportunities offered by the hard xray domain.
There are several good reasons to use this technic:- A high-resolution monochromator combined with high resolution hemisphericalanalyzers allow to perform measurements with a resolving power of about 100000!
- Double Core Hole dynamics [3-7] are measured with a very good signal/noise ratio,- Post Collision Interaction [8-9], much stronger than in the soft X-ray domain, areleading to interesting effects.
- Strong translational [10], vibrational [11] and rotational [11, 12] recoils occurring athigh photon energy can finely observed.
- Photoionization dynamics of clusters can be obtained (see talk of Minna PATANEN).
After showing recent results, I will discuss some scientific perspectives of this technic.
References[1] M. N. Piancastelli et al., Rep. Prog. Phys. 83 016401 (2020)[2] M. Oura et al., New. J. Phys. 21 043015 (2019)[3] R. Püttner et al., Phys. Rev. Lett. 114 093001 (2015)[4] G. Goldsztejn et al., Phys. Rev. Lett. 117 133001 (2016)[5] O. Travnikova et al., Phys. Rev. Lett. 116 213001 (2016)[6] O. Travnikova et al., Phys. Rev. Lett. 118 213001 (2017)[7] T. Marchenko et al., Phys. Rev. Lett. 119 133001 (2017)[8] R. Guillemin et al., Phys. Rev. Lett. 109 013001 (2012)[9] S. Kosugi et al., Phys. Rev. Lett. 124, 183001 (2020)[10] M. Simon et al., Nat. Commun. 5 4069 (2014)[11] E. Kukk et al., Phys. Rev. Lett. 121 073002 (2018)[12] D. Céolin et al., PNAS 116 4877 (2019)2p2-1 : Contributed

Depth-resolved HAXPES study of (Ag,Cu)(In,Ga)Se2 thinfilm solar cells
Natalia M. Martin1, Tobias Törndahl1, Erik Wallin2, Konstantin A. Simonov3,*,
Håkan Rensmo3 and Charlotte Platzer-Björkman1
1

Solar Cell Technology, Department of Materials Science and Engineering, Uppsala University,
75121 Uppsala, Sweden
2
Solibro Research AB, Vallvägen 5, 75651 Uppsala, Sweden
Present address: EVOLAR AB, 75651 Uppsala, Sweden
3
Molecular and Condensed Matter, Department of Physics and Astronomy, Uppsala University,
75121 Uppsala, Sweden*
Present address: Swerim AB, Department of Materials and Process Development, 16407 Kista,
SwedenThin film solar cells based on Cu(In,Ga)Se2 (CIGS) absorbers have shown high and stableefficiencies for both laboratory cells and industrial modules with record cell efficiencies of
23.4%. To reach closer to the theoretical maximum efficiency of around 30%, further reductionsof optical and electrical losses are needed. Recent works show that silver (Ag) alloying in CIGS
to form (Ag,Cu)(In,Ga)Se2 (ACIGS) leads to higher device efficiencies as compared to similar
CIGS devices without Ag. Moreover, Ag incorporation increases the band gap, which can be
exploited to pave the way for high band gap applications such as tandem solar cells. Further, a
postdeposition treatment (PDT) based on alkali metal fluorides after absorber formation has beenstudied recently and is known to improve the efficiency in CIGS solar cells. The exact role of thesilver and/or alkali elements is intensively discussed, but it is clear that interface and grainboundary effects are important in (A)CIGS solar cells. It is likely that a redistribution of theabsorber elements near the surface region may occur during the alkali PDT and some works showinterface formation in CIGS solar cells subjected to a metal fluoride post deposition treatment.
In this work we employed HAXPES at varying photon energies to study the near surface
region of PDT-ACIGS absorbers, which have been exposed to different metal fluorides during
preparation, and the interface with a CdS buffer layer. Two different alkali PDT are compared,
RbF and CsF, to investigate how the choice of the metal fluoride treatment affects thebuffer/absorber interface. In particular, the chemical and electronic properties of CdS/ACIGS
interfaces in terms of intermixing, energy band alignment and composition for a set of device
relevant samples have been studied. The results show that the electronic structure at the
CdS/ACIGS interface does not change for the different PDTs. However, the ACIGS compositionat the near surface region seems to change depending on the applied PDT process. Possible
reasons for this will be discussed. The results give insights into how selective alkali PDT couldchange the ACIGS surface composition, which may influence the solar cell behavior.

2p2-2 : Contributed

Using Hard X-ray Photoelectron Spectroscopy to Probe
Rechargeable Battery Interfaces
Andrew J. Naylor 1, Ida Källquist 2, L. O. Simon Colbin 1, Marco Carboni 1,
Maria Hahlin 1,2, Reza Younesi 1, Kristina Edström 1, and Daniel Brandell 1
12

Department of Chemistry – Ångström Laboratory, Uppsala University, Box 538, 751 21
Uppsala, Sweden

Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden

Battery ageing often begins at the interfaces between electrodes and electrolyte
through phenomena such as phase transformation, surface layer (interphase) formation,
cationic/anionic redox reactions and metal dissolution. By employing advanced
characterisation techniques, we can gain a better fundamental understanding, on the atomic
level, of the interfacial processes occurring within modern rechargeable batteries. Hard
X-ray photoelectron spectroscopy (HAXPES) is perfectly suited to determining
composition, oxidation states, and bonding environments within the surface regions (~50 nm
depth) of battery materials. Through tuning of the incident X-ray energy, a non-destructive
depth profiling experiment can offer a true surface vs. bulk picture. Correlation of such datafrom advanced characterisation with electrochemical cycling performance allows for greater
understanding of ageing mechanisms and informs strategies to stabilise interfaces for ultrahigh performance batteries.
I will present examples of our research from the Ångström Advanced Battery Centre and how
HAXPES depth profiling plays a large role in many of our studies of Li-, Na-, and K-ion
batteries. For Li-rich cathode materials (e.g. Li[Li0.2Ni0.2Mn0.6]O2, Li2VO2F), we havecharacterised cationic and anionic redox activity through the use of HAXPES, as well as
determined degradation mechanisms, which can result in rapid capacity fading [1]. Strategies
including material doping, particle coatings and electrolyte additives have been developed to
improve performance. For Na-ion batteries, we are developing novel fluorine-free and nonflammable electrolytes; HAXPES is employed to study the composition and stability ofinterphase layers formed on hard carbon electrodes [2]. Finally, for K-ion batteries we havedemonstrated the poor stability of interphase layers formed on graphite electrodes through
HAXPES depth profiling [3]; the challenge remains to develop high-performance electrolytes forsuch systems.
References[1] I. Källquist, A. J. Naylor, C. Baur, et al., Chem. Mater. 31 (16), 6084-6096 (2019).
[2] L. O. S. Colbin, R. Mogensen, A. Buckel, et al., Adv. Mater. Interfaces 8, 2101135 (2021).
[3] A. J. Naylor, M. Carboni, M. Valvo, et al., ACS Appl. Mater. Interfaces 11 (49), 45636-45645 (2019).

2p2-3 : Invited

Operando high pressure catalytic studies using
HAXPES
Blomberg Sara
1

Dept. Chemical Engineering, Lund University, Sweden

Performing fundamental operando catalysis studies under realistic conditions is key to further
develop and increase the efficiency of industrial catalysts. To gain knowledge on an atomistic
level, simplified model systems are often used and studied at well-controlled conditions at low
pressure using surface-sensitive techniques. These conditions differ significantly compared toindustrial applications, where the catalysts are operating at atmospheric pressure and above.
There is therefore an ongoing debate, on whether the results achieved at low pressures are
relevant also for real applications. The discussion introduced the concept “pressure gap” between
fundamental research and applications and inspired research to attempt to bridge this gap. Overthe last decades, a great effort has been made to develop surface-sensitive techniques to operate
at more realistic conditions. Ambient Pressure X-ray Photoelectron Spectroscopy (AP-XPS) is a
powerful tool in the field of surface science and catalysis with the capability of probing both gas
phase adjacent to the catalysis surface simultaneously as the chemical composition of thecatalyst. By using grazing incidence HAXPES, surface-sensitive operando studies at highpressure can be performed.
We have used operando HAXPES to study model catalysts in a wide pressure range to achieve
a complete understanding of the catalytic process at surfaces under industrial conditions.
Recently we performed an operando CO oxidation study at 1 bar total pressure using a novel
XPS setup at Petra III, DESY in Germany, aiming to bridge the pressure gap (Fig 1)[1].

Fig. 1: The light-off region for CO oxidation using a Pd(100) model catalysts at a total pressure of 1 bar
The CO2 gas-phase peak presence is a clear marker of the light-off of the catalyst, which is around 405°C. The intensity of the spectra is color-coded, ranging from dark blue to yellow, where the latter
indicates high intensity.

References[1] S Blomberg, U Hejral, M Shipilin, S Albertin, H Karlsson et al, ACS Catalysis 11, 9128-9135 (2021)

2p2-4 : Contributed

Co(0001) Fischer-Tropsch observations at 550mbar (andabove) using a virtual cell approach and hard X-rays
Patrick Lömker1,2, David Degerman2, Mikhail Shipilin2, Christopher Goodwin2,
Hsin-Yi Wang2, Alexander Holm2, Markus Soldemo2, Heshmat Noei1, Michael
Wagstaffe1, Raffael Rameshan4, Christoph Schlueter1, Anders Nilsson2
and Peter Amann2
1

2

Photon Science, Deutsches Elektronen-Synchrotron DESY, DE-22607 Hamburg
Fysikum, Stockholm University, AlbaNova University Center, SE-10691 Stockholm
3Institute of Physical Chemistry, University of Innsbruck, AU-6020 Innsbruck SE
4
Institute of Materials Chemistry, Technical University Vienna, AU-1060 Vienna

Catalytical reactions are both societally important and difficult topics for fundamental research. Theima ce ca be ea il dem
a ed b ecalli g he med c (fe ili e , f el , la ic).
Especially in combination with the need to move towards CO2 neutral procedures, long standing
paradigms need to be challenged. Fischer-Tropsch reactions in particular can be run to produce very
different distributions of valuable hydrogenated carbons, that can be used in fuels and energy distribution
schemes of the future completely based on regenerative resources.
Despite knowing that this catalytic reaction exists, available literature detailing the debated reaction
mechanisms is lacking [1, 2]. Indeed, only indirect measurements (e.g. by QMS), observations far awayfrom reaction conditions (XPS < ~10mbar) or after the reaction can be found. As seen by many
publications XPS can address the reaction mechanisms in question. However, combining ultra-highvacuum (UHV), as it is required to transfer photoelectrons without scattering and high pressures (above 1bar), as it is required for the catalytic reaction, has posed significant technical challenges and caused apressure gap above the ~10mbar range.
The POLARIS setup (Stockholm University) is in operation at P22, PETRA III [3] and can readily be
employed above this pressure gap by utilizing a virtual cell concept. Here we set out with the goal ofobserving the FT reaction at pressures as close as possible to the pressures applied in industrial catalysis
and compare isobars at 150, 550 and 1000 mbar of undiluted reactants.. Onto the single crystalline cobalt
we direct mixtures of CO:H2, CO2:H2 and CO:CO2:H2. We obtain Co2p, C1s and O1s core level spectraand quantify the adsorbed species under these conditions. Our results reflect recently published resultsfrom operando STM[4] and show significant differences to findings from post-reaction XPS[5].

References[1] J. Gaube et al. J. Mol. Catal. Chem. 283, 60–68 (2008).
[2] Z. W. Ulissi et al. Nat. Commun. 8, 14621 (2017).
[3] P. Amann et al. Rev. Sci. Instrum. 90, 103102 (2019).
[4] P. Chai et al. J. Phys. Chem. C 125, 22223–22230 (2021).
[5] B. Böller et al. Nat. Catal. (2019). doi:10.1038/s41929-019-0360-1

2p2-5 : Contributed

Laa

HAXPESGaN

E. Martine 1, T. Spelta 1, P. Fernandes Paes Pinto Rocha 1, M. Veillerot 1, B. H ot
1
, W. Vandendaele 1, L. Vauche 1, B. Salem 2
1
2

Univ. Grenoble Alpes, CEA, Leti, F-38000 Grenoble, France
Univ. Grenoble Alpes, CNRS, LTM, F-38000 Grenoble, France

High-electron-mobilit transistors (HEMTs) based on AlGaN/GaN heterostructures are being
developed for high power electronics. The presence of a two-dimensional electron gas (2DEG) at
the AlGaN/GaN interface enables reaching high electron mobilit (>1500 cm2.V-1.s-1). For safet
reasons, normall -off HEMTs are requested and can be obtained b the full recess approach,based on the removal of the AlGaN la er underneath the gate. The dielectric (Al 2O3) and metal
gate are deposited on the etched GaN surface to create a metal-insulator-semiconductor (MIS)
structure, giving rise to the so-called MIS-HEMTs [1].
The final device properties strongl depend on the qualit of the buried Al 2O3/GaN interface[2]. Advanced chemical characteri ation of this critical interface is thus mandator . Laborator
HAXPES has recentl appeared and its use is quickl rising for optimi ing technological devices[3]. It is here a promising technique to investigate a more realistic Al2O3/GaN interface, e. g. witha thick Al2O3 la er. We use it to investigate the impact of Al2O3 thickness, growth process andpost-deposition anneal on the GaN surface oxidation and stoichiometr .

. 1: Compa i on of he ampling dep h fo he Al2O3(20 nm)/GaN ack i h C K and Al KD o ceand Ga 2p pec a mea ed a 45 i h a C K o ce h o gh a ing Al 2O3 hickne e .

R[1] J. He et al., Advanced Electronic Materials 7, 2001045 (2021).
[2] L. Vauche et al., ACS Applied Electronic Materials 3 (3), 1170 (2021).
[3] O. Renault et al., Surface and Interface Anal sis 50 (11), 1158 (2018).

2p2-6 : Contributed

Strong Dimensional Character in layered ReS2 and ReSe
studied by complimentrary x-ray photoelectron spectroscopy
Dibya Phuyal 1,2, Fredrick O.L. Johansson3,4, Debjani Sarkar5, Mahmoud AbdelHafiez5
1
2

Dept. of Applied Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden
Dept. of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK
3
Dept. of Chemistry, KTH – Royal Institute of Technology, SE-100 44 Stockholm, Sweden
4
CNRS, Institut des NanoSciences de Paris, Sorbonne Université, Paris 75005, France
5
Dept. of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden

Using complimentary x-ray photoelectron spectroscopy techniques, we study the electronic
structures of two-dimensional van der Waals (vdW) compounds ReS2 and ReSe2. The in-planeand out-of-plane valence band character are studied by varying the polarization of incoming
photons, we show the out-of-plane transition metal dz2 and chalcogen pz orbitals do not contributesignificantly to the top of the valence band, supporting a weak interlayer coupling in this class of
vdW materials. Furthermore, ReS2 shows two distinct Re sites that are linked to strong intraplane Re-Re metallic bonds. Resonant Auger Spectroscopy (RAS) taken across the S K-edge for
ReS2 is employed to obtain electron delocalization times across the conduction band down to theattosecond time scale. The intrinsic electron dynamics of ReS2 shows a significant difference indelocalization times between intra and inter-plane orbitals. Our results are supported by density
functional theory calculations that provide insight into the layer dependent properties of rhenium
dichalcogenides and highlight their place among two-dimensional crystals.

EF

EF

Grazing
Incidence

2485

10

2480

2480
2475

hv = 4000 eV

5010
Binding Energy (eV)50NormalIncidence

2485

2475

hv = 4000 eV

2490

Excitation Energy (eV)

ReSe2

2495

2490

Excitation Energy (eV)Intensity (Norm. to Area)

ReS2

2495

Out-of-Plane
In-PlaneOut-of-Plane
In-Plane

ReS2 S KLL

2470
2110

2120

Kinetic Energy (eV)

ReS2 S KLL

2470
2110

2120

Kinetic Energy (eV)Fig. 1: (left) Hard -x-ray photoemission spectra of the valence band (VB) for ReS2 and ReSe2 withdifferent light polarizations to study the inter and intra-plane valence states. ReS2 shows a valence band
maximum that changes for in-plane and out-of-plane states. (right) Resonant Auger maps of S KLL for
ReS2 that show different delocalization pathways for in-plane and out-of-plane states.

3a1-1 : Plenary

Ei gface ca a

i h a bie

e

ic a

e

e XPS

Bongjin Simon Mun1
1

Department of Physics and Photon Science,
Gwangju Institute of Science and Technology, Korea
A synchrotron-based ambient pressure XPS (AP-XPS), first reported from ALS in 2001, hasmade a significant impact on the community of surface science over the years. By exploring thenature of surface under elevated pressure condition, many stimulating results have been reported,
clearly putting a new road map on the surface science. While the application of AP-XPS covers
the various fields of surface science, e.g. from traditional gas molecule interaction on solid
surface to liquid/solid interface in electrochemistry, the community of surface catalysis has
gained much benefits from the progress of AP-XPS.
In this presentation, various surface catalytic reactions on metal surfaces will be explored withthe use of AP-XPS, i.e. CO2 dissociation on Rh (111), CO oxidation on Pt3Ni(111) and Pt3Co(111). [1,2] An ambient pressure scanning tunneling microscope (AP-STM) is accompanied todeliver the information of surface morphology under reaction condition, adding a new dimension
in analy ing surface chemical reactions in real time. In addition, the pro and cons of using hard
x-ray in AP-XPS is also presented.

. 1: Ti e- a e i
NAP-XPS a 300 K.

ib e aihe Rh(111)face i 0.1 T

CO2i g NAP-STM a d

Refe e ce[1] Jeongjin Kim, Hyunwoo Ha, Won Hui Doh, Kohei Ueda, Ka uhiko Mase, Hiroshi Kondoh, Bongjin Simon Mun,
Hyun You Kim, Jeong Young Park, Na e c
ica i , 11, 1-9 (2020).
[2] Jeongjin Kim, Woong Hyeon Park, Won Hui Doh, Si Woo Lee, Myung Cheol Noh, Jean-Jacques Gallet, Fabrice
Bournel, Hiroshi Kondoh, Ka uhiko Mase, Yousung Jung, Bongjin Simon Mun, Jeong Young Park, Scie ce
Ad a ce , 4, eaat3151 (2018)

3a1-2 : Invited

The Electronic Structure of Degenerately doped Ga2O3 Thin
Films Studied by HAXPES
Jiaye Zhang1, Joe Willis2, 3, 4, Zhenni Yang1, Tien-Lin Lee4, David Scanlon3, 4 and K.
H. L. Zhang1*
1State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry andChemical Engineering, Xiamen University, Xiamen 361005, P.R. China
2
Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ,
United Kingdom
3Thomas Young Centre, University College London, Gower Street, London, WC1E 6BT, United
Kingdom4
Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, OX11 0DE,
United Kingdom

Ga2O3 is emerging as a promising wide bandgap semiconductor for high-power electronics andsolar-blind ultraviolet photodetector. It is highly desirable to dope it with controllable carrier
concentrations for different purpose of applications. This talk reports the realization of degenerate
doping of Ga2O3 with Si (SGO) thin films with carrier concentrations ranging from 5 ×10 18 up to
2.6 ×1020 cm-3. A record high conductivity of 2520 S/cm and mobility of 60 cm2/V s was achieved.
The SGO films show a high transparency over a wide spectrum from visible to deep UV. Hard xray photoelectron spectroscopy (HAXPES), optical spectroscopy and DFT calculations were also
performed to elucidate insights on the optical and electronic structures. HAXPES at the valenceband observed the widening of bandgap as a result of occupation of the conduction band (CB) andthe shrinkage of bandgap associated with many-body interaction. Supplemented with DFT, wedemonstrate that the bandgap shrinkage mainly result from the change of CB induced by mutual
electrostatic-interaction. Because the Si energy level is sitting 3 eV above the CB bottom, there islittle hybridization between Si orbital and Ga 4s derived CB, leaving the CB edge unperturbed anda small electron effective mass maintained though the doping level is high.

References[1] Zhang, J.; Shi, J.; Qi, D.-C.; Chen, L.; Zhang, K. H. L.; APL Mater., 2020, 8, 020906.
[2] Zhang, J.; Willis J.; Yang Z. N.; Xu X.Y.; Wang L.-S.; Lee T. -L.; Chen, L.; Scanlon D.; Zhang, K. H. L.; Cell
Reports Physical Science, 2022, 3, 100801.

Abstract
Poster session

P1

Resonant Auger of Xe on transition metal substrates
Elin Berggren1, Fredrik O.L. Johansson 2,3, Mattis Fondell4, Denis Céolin5 andAndreas Lindblad 1
1 Division of X-ray Photon Science, Department of Physics and Astronomy, Lägerhyddsvägen 1,

75237 Uppsala

2 Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005, Paris, France
3 Division of Applied Physical Chemistry, Department of Chemistry, KTH

Technology, SE-100 44 Stockholm, Sweden

Royal Institute of

4 Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-

Zentrum Berlin f r Materialien und Energie, 12489 Berlin, Germany

5 Synchrotron SOLEIL, l Orme des Merisiers, Saint-Aubin, F-91192 Cedex Gif-sur-Yvette,

FranceA study of the Auger decay process is presented for solid Xe on 3d transition metals withvaried work function. Resonant Auger spectroscopy have shown to be a valuable method to study
charge transfer and electronic structures of solids using the core-hole clock method [1]. In thiswork, the Xe L3 edge was studied on a Xe monolayer adsorbed on metal surfaces using hard Xray spectroscopy. Using core excitations from Xe 2p 3/2 level we have recorded the resonant Auger
spectra with electron kinetic energies in the LMM kinetic energy region. This was done forseveral excitation energies and the partial Auger (decays from charge transfer states where theelectron in the excited state have tunneled away) and Raman (decays from states where theexcited electron has remained on the atom with the core-hole) yields were extracted as well as the
charge transfer time of core-excited states. We compare the results from the condensed case withthat of Xe Resonant Auger from a gas-phase sample [2]. For instance, the charge transfer channel
is not available in the isolated atom case.
References[1] P. A. Brühwiler, O. Karis, N. Mårtensson, Rev. Mod. Phys. 74 No. 3 (2002)[2] R. K. Kushawaha, K. Jänkälä, T. Marchenko, G. Goldsztejn, R. Guillemin, L. Journel, D. Céolin, J.-P. Rueff, A. F.
Lago, R. Püttner, M. N. Piancastelli, and M. Simon, Phys. Rev. A 92, 013427 (2015)

P2
In-Plane Orientation of the 4f-Orbital Distribution in YbRh2Si2
Probed by Linear Dichroism in Core-Level HAXPES
Akane Ose1,2, Satoru Hamamoto1,2, Toshiyuki Kashiuchi1,2, Goro Nozue1,2, Hidenori Fujiwara1,2,
Yuina Kanai-Nakata2,3, Shin Imada2,3, Atsushi Yamasaki2,4, Atsushi Higashiya2,5,
Kenji Tamasaku2, Takayuki Kiss1, Makina Yabashi2, Tetsuya Ishikawa2, Arata Tanaka6,
Takao Ebihara7, and Akira Sekiyama1,2
1Grad. Sch. of Eng. Sci., Osaka Univ., 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
2
RIKEN SPring-8 Center (RSC), 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
3
Dept. of Phys. Sci., Ritsumeikan Univ., 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
4
Fac. of Sci. and Eng., Konan Univ., Okamoto Higashinada, Kobe, Hyogo 658-8501, Japan
5
Fac. of Sci. and Eng., Setsunan Univ., 17-8 Ikedanaka-machi, Neyagawa, Osaka 572-8508, Japan
6
Grad. Sch. of Adv. Sci. and Eng., Hiroshima Univ., 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima
739-8530, Japan
7
Dept. of Phys., Shizuoka University, 836 Ohya, Suruga, Shizuoka 422-8529, Japan

Rare-earth Ce and Yb compounds exhibit various intriguing physical properties such as non-Fermi-liquidbehavior and unconventional superconductivity near the quantum critical point (QCP). The Yb (Ce) 4forbital holes (electrons) with the 4f13 (4f1) configurations are responsible for these properties. Such 4f
electrons often show the dual nature of the localization and itinerancy by the hybridization with theconduction electrons. The low-temperature 4f electronic phases as a function of the hybridization strengthand temperature is often represented by the Doniach phase diagram [1]. It has been recognized that the 4f
spatial distribution and its orientation determined by the local crystalline electric fields (CEF) in thelocalized picture is important for clarifying the physics of the strongly correlated 4f electron systems [2].
YbRh2Si2 with the tetragonal ThCr2Si2-type crystal structure shows the non-Fermi-liquid behavior as
demonstrated by the electrical resistivity and specific heat [3][4]. Therefore, YbRh2Si2 is considered to belocated near QCP where the RKKY interaction and the Kondo effect are competed. Its 4f-orbital
symmetry, especially the in-plane orientation of the 4f charge distribution, has not been rigorously
clarified yet.
Here we show the 4f ground-state symmetry of YbRh2Si2 revealed by the linear dichroism (LD) in angleresolved hard X-ray photoelectron spectroscopy (HAXPES) at BL19LXU of SPring-8 with the two-axis
angle manipulation [5]. Contrary to the previous LD-HAXPES study with the imperfect experimental
condition (lack of the azimuthal angle dependence), we have found the CEF-split 4f ground state ofYbRh2Si2 a he 7 symmetry with the mixture of |Jz = ±5/2⟩ and |∓ 3/2⟩, where Jz stands for the z
component of the total 4f angular momentum J = 7/2 [6]. We have also revealed that the 4f charge
distribution of YbRh2Si2 as well as valence-fluctuating YbNi2Ge2 is elongated along the transition-metalsites while that of YbCu2Si2 is expanded to the Si sites [6][7]. We also discuss the qualitative difference of
the in-plane orientation of the 4f distribution in the ThCr2Si2-type crystal structure from that in the Cecompounds, of which the similarity with respect to the electron-hole symmetry between the Ce and Yb
systems has been often pointed out.

References[1] S. Doniach, Physica B, 91, 231 (1977).
[2] J.-P. Rueff et al., Phys. Rev. B 91, 201108(R) (2015).
[3] O. Trovarelli et al., Phys. Rev. Lett. 85, 626 (2000).
[4] O. Trovarelli et al., Physica B 281&282, 372-373 (2000).
[5] H. Fujiwara et al., J. Synchrotron Rad. 23, 735 (2016).
[6] T. Mori et al., J. Phys. Soc. Jpn. 83, 123702 (2014).
[7] H. Yamaoka et al., Phys. Rev. B 82, 035111 (2010).

P3

Magnetometry of Buried Co-based Nanolayers by
Hard X-ray Photoelectron Spectroscopy
Andrei Gloskovskii 1, Gerhard Fecher2, Katrin Ederer1, Ilja Schostack1, andChristoph Schlueter 1
1

Photon Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
2
Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

The intensity and shape of photoelectron lines of magnetic materials depend on the relativeorientation of the sample magnetization, the X-ray beam polarization and the spectrometer axis,
i.e. the electron emission direction. In the hard X-ray regime, the beam polarization can beconveniently modified utilizing the phase shift produced by a diamond phase plate in the vicinityof a Laue or Bragg reflection. A single-stage in-vacuum phase retarder is installed andcommissioned in 2020 at the HAXPES beamline P22 at PETRA III (Hamburg, Germany) [1].
The electronic and magnetic properties of CoFe and Co-based Heusler nanolayers were studied
using the linear and circular magnetic dichroism in the angular distribution of photoelectrons. The
layers were remanently magnetized in-situ and Co 2p1/2 and 2p3/2 core levels were probed at room
temperature [2-3]. Both the polarization-dependent spectra and the dichroism indicate that thelines of the multiplet extend over the entire spectral range. In particular, the dichroism does notvanish between the two main parts of the spin–orbit doublet.
References[1] C. Schlueter, A. Gloskovskii, K. Ederer et al., AIP conference proceedings 2054(1), 040010 (2019).
[2] G. H. Fecher, D. Ebke, S. Ouardi et al., SPIN 04, 1440017 (2014).
[3] P. Swekis, A.S. Sukhanov, Y.-C. Chen, A. Gloskovskii et al., Nanomaterials 11, 251 (2021).

P4

B lk Elec ronic S a e of A -Ga-Ce and Cd-Ce Q asicr s alline
Appro iman s Probed b Hard X-ra Pho oemission Spec roscop
Goro No e1,2, Akane O e1,2, Ha a o Ha hi me1,2, Hidenori F ji ara1,2,
Taka ki Ki 1, Sa or Hamamo o2, Kenji Tama ak 2, Makina Yaba hi2,Tea I hika a2, A
hi Higa hi a3, A
hi Yama aki4, Shin Imada5,A

a Mo o ri6, Farid Labib6, Shin aro S

ki6, R ji Tam ra6, Akira Seki ama1,2

1 Grad a e School of Engineering Science, O aka Uni er i , To onaka, O aka 560-8531, Japan
2 RIKEN SPring-8 Cen er, Sa o, H ogo 679-5158, Japan
3 Fac lof Science and Engineering, Se

4 Fac lof Science and Engineering, Konan Uni er i , Kobe, H ogo 658-8501, Japan

5 Depar men of Ph ical Science , Ri

nan Uni er i , Ne aga a, O aka 572-8508, Japanmeikan Uni er i , K a, Shiga 525-8577, Japan

6 Depar men of Ma erial Science and Technolog , Tok o Uni er i of Science, Tok o 125-8585, JapanS ronglcorrela ed rare-ear h ba ed q a icr

al and appro imana rac m cha en ion d e o niq e q an m cri ical phenomena [1]. Among hem, Ce-ba ed 1/1q a icr

alline appro iman A 60.3Ga26.1Ce13.6 and A 59.2Ga25.7Ce15.1 ha e recen l beende eloped, ofhich herongl correla ed Ce 4f elec ronic

differen . In he rongl correla ed 4f-elec ron

a e co ld be mallem , re ealing locali ed or i inerancharac er of 4f elec ron i impor an o nder and he ph ical proper ie like a q an m
cri ical phenomena. We ha e performed hard X-ra pho oemi ion pec ro cop(HAXPES) for he A -Ga-Ce appro iman o find o he charac er of 4f elec ron .
HAXPES of he q a icr
8

i h energ

alline appro iman

a carried oin BL19LXU of SPring-

re ol ion of 250 meV a h 𝜈 = 7.9 keV. In he Ce 3d core-le elpho oemi ion pec ra, he 3d 94f 0 final- a e pec raleigh indica ing he i ineran 4f

charac er i negligible for bo h compo nd . Thi re l indica e ha he 4f elec ron arehighl locali ed in he A -Ga-Ce appro iman . On he o her hand, he 3d 94f 1 final- a e
m l ipler c regge ing he ionic-like locali ed 4f elec ronic

ppre ed or meared ohere i

ae i

rongl

in he pec ra of A -Ga-Ce appro iman . I i kno n ha

he chemical di order (in erchange of A

and Ga i e ) in he A -Ga-Ceappro iman . Therefore,e ha e al o performed he Ce 3d core-le el HAXPES for a

Cd-Ce appro iman

he chemical di order and fo nd he clear 3d 94f 1 m l iple

i ho

r c re in he Ce 3d pec r m of he Cd-Ce appro iman . O r re l

gge

ha he

chemical di order rongl infl ence he elec ronic a e of he A -Ga-Ce appro iman .
Reference[1] K. Deg chi e a , Na . Ma er 11, 1013 (2012).

P5

Electronic structure of thermoelectric
Heusler-type Co2MnSi1-xAlx compounds
Hidetoshi Miyazaki1, Yoshiki Sekita1, Kosuke Watanabe1,
Akira Yasui2, Yasumasa Takagi2, Yuya Sakuraba3, and Yoichi Nishino1
1

Nagoya Institute of Technology, 466-8555, Nagoya, Japan
2
JASRI/SPring-8, Sayo, Hyogo 679-5198, Japan
3
National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, JapanThe half-metallic Heusler-type Co2MnSi compound is expected to be used as a thermoelectricmaterial for high-temperature applications because of its high power factor at hightemperatures.[1] In the Co2MnSi1-xAlx compounds, the sp electrons, which are many-spin
electrons, become the main carriers, and a rigid-band shift of the Fermi level to the half-metal gap
edge may result in a dramatic change in the Seebeck coefficient.[2] In this study, we report theresults of thermoelectric properties and electronic structure in Co2MnSi1-xAlx compounds.
The Co2MnSi1-xAlx compounds was prepared by arc melting in Ar atmosphere and sintering at
1173 K for 5 min by pulsed current sintering under pressure of 50 MPa. The photoelectron
spectroscopy measurements were performed at BL47XU of SPring-8 using an excitation photon
energy (hQ) of 7940 eV.
Fig. 1 shows the valence band photoemission spectra of
Co2MnSi1-xAlx compounds. In the range of x = 0 to 0.5,
where the power factor increases with increasing Al
substitution, the shape of the photoemission spectra does
not change significantly, and the electronic structurechanges in a rigid band model, shifting to the lower
binding energy side with deceasing carrier. In the range of
0.5, the shape of the photoelectron spectrum does notchange significantly. On the other hand, for x > 0.5, where
the power factor decreases abruptly, the photoelectron
spectrum becomes broadened due to the decrease in the
structural ordering. The present study shows that the rigid
band model control of the electronic structure is effective
for material design even in systems with a half-metal-likeelectronic structure.

References[1] K. Hayashi et al., J. Electron. Mater. 46 (2017) 2710.
[2] Y. Sakuraba et al., Phys. Rev. B. 81 (2010) 144422.

Fig. 1: Valence band photoemission
spectra of Co2MnSi1-xAlx compoundswith hQ = 7940 eV.

P6Valence fluctuation in thermoelectric material YbSi2
probed by HAXPES
Kentaro Kuga1, Masaharu Matsunami1, Hidenori Fujiwara2, Goro Nosue2,
Akane Ose2, Akira Yasui3, Satoru Hamamoto4, Masaki Oura4, Tsunehiro Takeuchi1
1

2

Toyota Tech. Inst., 2-12-1 Hisakata, Tempaku-ku, Nagoya, Aichi 468-8511, Japan
Grad. Sch. of Eng. Sci., Osaka Univ., 1 Machikaneyamacho, Toyonaka, Osaka 560-8531, Japan
3
JASRI, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
4
Riken SPring-8 Center, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, JapanYbSi2 is a high-performance thermoelectric material with the second highest Peltier coefficient(S/U, where S: Seebeck coefficient, U : electrical resistivity) among the reported materials and thehighest thermoelectric power factor (S2/U) among the Yb-based materials. The thermopower isdetermined by the density of state near the Fermi energy and it is important to investigate theelectronic state. Because Yb 4f electron can have both itinerant and localized feature, core level
HAXPES will help us to deeply understand the electronic state of Yb 4f electron.
Figure 1(a) shows the Yb 3d5/2 core level HAXPES spectrum at 20 K. Yb2+ and Yb3+
3d5/2 peaks are well separated which indicate the mixed valence state. Figure 1(b) shows thevalence band spectrum at 20 K. Yb2+ 4f7/2 peak locates just below the Fermi energy, suggesting
the Kondo resonance peak and the contribution of 4f electron to the transport property.
These results indicate valence fluctuating state which is similar to valence fluctuating materials
YbAl3 and D-YbAlB4 with high thermoelectric power factors [1,2]. In the presentation, we will
also show the SXPES spectra and explain in detail.

Fig. 1: Yb 3d5/2 core level (a) and valence band (b) HAXPES spectra.

References[1] H. J. van Daal, P. B. van Aken, and K. H. J. Buschow, Phys. Lett. A 49, 246 (1974).
[2] K. Kuga, M. Matsunami, S. Singh, S. Nakatsuji, and T. Takeuchi, Appl. Phys. Lett. 119, 223905 (2021).

P7

Relationship of Ce 4f-5d Coulomb Repulsion on CeT2X2(T = Cu, Ru; X = Si, Ge): Resonant HAXPES Study
Kojiro Mimura1,2, Gen Isumi1, Masaichiro Mizumaki2, Norimasa Sasabe2,
Akira Yasui2, Yu Akedo1, Taku Kawabata1, Ryohei Shimokasa1,2,
Yoshinori Shibagaki1, Naomi Kawamura2, Eiji Ikenaga3, Satoshi Tsutsui2,4,Hitoshi Sato5, Takayuki Uozumi1, Tatsuma D. Matsuda6, and Yoshichika Ōnuki7
1

Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531, Japan
2
Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198, Japan
3
IMaSS, Nagoya University, Nagoya 464-8601, Japan
4
Graduate School of Science, Ibaraki University, Mito, Ibaraki 310-8512, Japan
5
HiSOR, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
6
Graduate School of Science, Tokyo Metropolitan University, Hachioji 192-0397, Japan
7
Center for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan

Electronic structure of CeCu2Ge2 (Kondo temperature: TK ~5 K) [1,2], CeCu2Si2 (TK = 10 K)[3-6], and CeRu2Si2 (TK = 20 K) [7] has been investigated by resonant hard x-ray photoemission
spectroscopy (rHAXPES) to discuss a relation between Ce 4f-5d Coulomb repulsion (Ufd) [8] andQuantum critical phenomena on the Doniach phase diagram. The rHAXPES experiments aroundthe Ce L3 absorption region at 20 K were performed at BL09XU of SPring-8 [9]. Ce 3d spectra of
all the three compounds consist of three features attributed to the 4f 0, 4f 1, and 4f 2 final states.
The photon-energy (hν) distribution of photoemission intensity, that is, constant initial state (CIS)
spectrum, of each final state shows distinct resonance enhancement. In particular, the peak
positions of CIS spectra depend on compounds. A theoretical analysis based on the single
impurity Anderson model was performed to reproduce the hν dependence of Ce 3d rHAXPES
and CIS spectra. The resonance enhancement with hν of all the three compounds is well
explained by Ufd, together with hybridization strength between 4f and conduction electrons andcharge transfer energy Δ equivalent to the energy position of bare 4f level. We found that the Ufd
becomes larger in order of CeRu2Si2 (1.70 eV), CeCu2Si2 (3.00 eV), and CeCu2Ge2 (3.80 eV).
This trend suggests that Ufd is one of intrinsic physical parameters to understand the Quantum
critical phenomena, even if the phenomena stem from the magnetic fluctuation.
References[1] F. R. de Boer et al., J. Magn. Magn. Mater. 63&64, 91 (1987).
[2] D. Jaccard et al., Phys. Lett. A 163, 475 (1992).
[3] F. Steglich et al., Phys. Rev. Lett. 43, 1892 (1979).
[4] Y. J. Uemura et al., Phys. Rev. B 39, 4726 (1989).
[5] A. Severing et al., Phys. Rev. B 39, 4164 (1989).
[6] A. T. Holmes et al., Phys. Rev. B 69, 024508 (2004).
[7] J. D. Thompson et al., Solid State Commun. 56, 169 (1985).
[8] S. Watanabe and K. Miyake, J. Phys.: Condens. Mater 23, 094217 (2011).
[9] E. Ikenaga, A. Yasui, N. Kawamura, M. Mizumaki et al., Synchrotron Radiat. News 31, 10 (2018).

P8

Charge transfer energy in iridates:
a Hard X-ray Photoelectron Spectroscopy study
Daisuke Takegami1, Deepa Kasinathan1, Klaus K. Wolff1, Simone G. Altendorf1,
Chun-Fu Chang1, Katharina Hoefer1, Anna Melendez-Sans1, Yuki Utsumi1,
Federico Meneghin1, 2, Thai Duy Ha1, 3, Chien-Han Yen1, 4, Kai Chen5,
Chang-Yang Kuo1, 6, Yen-Fa Liao6, Ku-Ding Tsuei6, Ryan Morrow7, Sabine
Wurmehl7, Bernd Büchner7, 8, Beluvalli-Eshwarappa Prasad1, Martin Jansen9,
Alexander C. Komarek1, Philipp Hansmann1, 10, and Liu Hao Tjeng1
1

Max Planck Institute Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany
2
Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy
3
Department of Electrophyiscs, National Chiao Tung University, 1001 Ta Hsueh Road, 30010
Hsinchu, Taiwan.

4

Department of Physics, National Tsing Hua University, 101 Kuang Fu Road, 30013 Hsinchu,
Taiwan56Institute of Physics II, University of Cologne, Zülpicher Straße 77, 50937 Cologne, Germany
National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, 30076 Hsinchu, Taiwan
7
Leibniz Institute for Solid State and Materials Research IFW Dresden, Helmholtzstraße 20,01069 Dresden, Germany
89Institut für Festkörperphysik , Technische Universität Dresden, 01062 Dresden, Germany
Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart,Germany
10
Department of Physics, University of Erlangen - Nuremberg, 91058 Erlangen, Germany

We have investigated the electronic structure of iridates in the double perovskite crystal structure
containing either Ir4+ or Ir5+ using hard x-ray photoelectron spectroscopy. The
experimental valence band spectra can be well reproduced using tight binding calculations
including only the Ir 5d, O 2p and O 2s orbitals with parameters based on the downfolding of
the density-functional band structure results. We found that regardless of the A and B cations, theA2BIrO6 iridates have essentially zero O 2p to Ir 5d charge transfer energies. Hence, double
perovskite iridates turn out to be extremely covalent systems with the consequence beingthat the magnetic exchange interactions become very long-ranged, thereby hampering thematerialization of the long-sought Kitaev physics. Nevertheless, it still would be possible torealize a spin-liquid system using the iridates with a proper tuning of the various competingexchange interactions

References[1] D. Takegami, D. Kasinathan, K. K. Wolff, S. G. Altendorf, C. F. Chang, K. Hoefer, A. Melendez-Sans, Y.
Utsumi, F. Meneghin, T. D. Ha, C. H. Yen, K. Chen, C. Y. Kuo, Y. F. Liao, K. D. Tsuei, R. Morrow, S. Wurmehl,
B. Büchner, B. E. Prasad, and M. Jansen et al., Phys. Rev. B 102, 045119 (2020).

P9

Observation of ferroelectric skewed band structure in
multiferroic BiFeO3

Shibei Huang1, Keita Ozawa2, Kei Shigematsu2, Masaki Azuma2, Akira Yasui3,
Eiji Ikenaga4, Norihiro Oshime5, Zihao Zhang1, Tomoko Okubo1, Jun Kano1
1

Graduate School of Natural Science and Technology, Okayama University, Japan
2
Laboratory for Materials and Structures, Tokyo Institute of Technology, Japan
3
Japan Synchrotron Radiation Research Institute, JASRI, Japan
4
Institute of Materials and Systems for Sustainability (IMaSS), Japan
5
National Institutes for Quantum Science and Technology, QST, Japan

Ferroelectric skewed band structure is understood as the combination of band structure andelectric polarization, which exhibits behavior as the electron energy level shifts according to
the depth in the polarization direction. By using angle-resolved hard X-ray photoelectron
spectroscopy (AR-HAXPES), the skewed band structure of ferroelectric BaTiO3 thin film wasobserved successfully [1]. For further study to clarify the semiconductor physical properties ofmultiferroics materials, in this research, we prepared single domain BiFeO3 (BFO) thin films
with downward polarization vertically oriented to the SrRuO3(~3 nm)/SrTiO3(111) substrate.
For the direct observation of ferroelectric band skewing structure, we performed AR-HAXPES
of multiferroic BFO thin films. As shown in Fig. 1, the depth profiles of Bi-4f atomic orbital
consists of two regions: the potential slope according to depth and polarization in the deeper
region (FEBS: ferroelectric band skewing), and the slope exhibits flat on the surface (SBS:
surface band skewing). Similar behavior is also observed in Fe-2p and the valence band.

Fig. 1: (a) AR-HAXPES spectra observed from emission angle 5° to 65° of Bi-4f5/2 and Bi-4f7/2 in the
40nm thick BFO. Black curve and dots are from the surface, purple curve and dots are from the deeper
region. (b) Depth dependence of binding energies of Bi-4f5/2 and Bi-4f7/2 in the 40nm thick BFO. Red
arrows indicate the inherent direction of the electric polarization for as-grown film.

Refe ence[1] N. O hi e e al., Sci. Rep. 10, 10702 (2020).

P10

Dy 3d Core-Level Photoemission Lineshape and Its
Correspondence with Chemical State
Shin Imada 1, Akinori Irizawa 1, and Kei Mitsuhara 1
1Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan

There are a variety of Dy (dysprosium) compounds that have been attracting strong
interest such as Dy-doped Nd-Fe-B permanent magnet. In the study of chemical state andelectronic state of Dy in such compounds, Dy 3d core-level photoemission (Dy 3d XPS) is
important. Since the binding energy of the Dy 3d core level is around 1300 eV, photoelectronenergy is as low as 200 eV when Al K D X-ray source is used. Then, the effect of the secondary
electrons background is quite serious and also the spectrum is quite surface sensitive. Therefore,
only very small number of experimental studies have been performed. In other words, hard
X-ray photoemission is expected to be a powerful tool.
Another aspect of Dy 3d XPS is that multiplet structures, due to exchange interaction between
3d core and 4f orbital, is expected. Such multiplet structures may sometimes be
mistakenly assigned to different chemical states. In Eu2+ compounds, for example, the structure in
the larger binding energy region of 3d XPS turned out to be nothing but a part of multiplet
structures [1].
In this study, Dy mental and Dy oxide have been studied by X-ray photoelectron spectrometer(PHI Quantes, Dual Scanning X-ray Photoelectron Microprobe) equipped with hard X-ray (CrKα) and soft X-ray (Al Kα) monochromatized sources at SR Center, Ritsumeikan University.
References[1] E.-J. Cho, S.-J. Oh, S, Imada, S. Suga, T. Suzuki, T. Kasuya, Phys. Rev. B 51, 3238 (2000).

P11

Re a ha d X- a h e i i
ale ce fl c a i ge-Yb(Al1- Fe )B4
T. H. Ni hi ka1, K. K ga2, H. F ji ara1, R. Himeno1, R. Ka ahara1, S. Hamamo o1,
K. Ni himo o1, T. Ki 1, A. Ya i3, N. Sa abe3, N. Ka am ra3, E. Ikenaga4,
M. Mi maki3, S. T
i3, K. Mim ra5, A. Seki ama1
1Grad. Sch. of Eng. Sci., O aka Uni ., 1-3 Machikane ama, To onaka, O aka 560-8531, Japan2
To o a Tech. In ., Nago a, Aichi 468-8511, Japan
3
JASRI, Sa o, H ogo 679-5198, Japan
4
IMaSS, Nago a Uni ., F ro-cho, Chik a-k , Nago a 464-8603, Japan
5
Grad. Sch. of Eng., O aka Pref Uni ., Sakai, O aka 599-8531, JapanThe rongl correla ed 4f-elec ron
em -YbAlB4
e hibincon en ional
percond c i ia ambien
pre re i h ero field belo 80 mK herea -YbAlB4
ho
Fermi liq id beha ior [1,2]. Ho e er, b dopingi h 1.4 % Fe in he Al i e , -YbAlB4 become ananomalo me allic a e and ho q an m cri icali like
-YbAlB4 [3]. When Fe i doped abo e 1.4 %, he alenceof Yb increa e rapidl , and hhe cri ical alence
fl c a ion i con idered o pla an impor an role in hemechani m of he anomalo proper ie [4]. Thi cri ical
alence fl c a ion i heore icall a rib ed o he
Co lomb in erac ion Ufd be een 4f elec ron andcond c ion elec ron [5]. Therefore, e ha e a emp ed oe al a e Ufd e perimen all b Yb 2 -5d re onan hard Xra pho oemi ion pec ro cop (rHAXPES) for -YbAlB4
doped i h Fe. The e perimen a carried o a BL09XU
of SPring-8 a a empera re of 20 K and an energ
re ol ion of 250 meV.
Ufd i e ima ed b he difference in he cen er-ofgra i energ and re onance energ of he Yb2+ and Yb3+
componen of he Yb 3d5/2 core-le el pho oelec ron
pec r m. A ho n in Fig. 1(a), he Yb 3d5/2 rHAXPES
a re onance enhancemen .
pec ra of -YbAlB4 ho
Con an Ini ial Sa e (CIS) pec ra are e rac ed frompec r m a each peak. CIS pec ra ho n in Fig. 1(b) gi edifferen re onance energie depending on he r c re andcompo i ion. From hi re l , e fo nd ha Ufd ho acompo i ion dependence.

(a)

(b)

. 1: (a) HAXPES ec a f-YbAlB4. (b) CIS
Yb 3d5/2 f
ec a f Yb2+ a d Yb3+. Thee ical li e i dica e e a ce
e eg

Refe e ce[1] Y. Ma mo o e al., Ph . Re . B 84, 125126 (2011). [2] S. Naka ji e al., Na . Ph . 4, 603 (2008).
[3] K. K ga e al., Sci. Ad ., 4, eaao3547 (2018).
[4] K. Mi ake and S.Wa anabe, Plilo . Mag. B97, 3495(2017).
[5] S. Wa anabe and K. Mi ake, J. Ph .: Conden . Ma er 23, 094217 (2011).

P12

S stematic charge distribution changes in Bi, Pb-3dtransition metal perovskite o ides

Tak mi Nishik bo1,2, Y ki Sakai1, Kengo Oka3, Masaichiro Mi maki4,
Tets Watan ki5, Takashi Mi oka a6 and Masaki A ma2,1
1

Kanaga a Instit te of Ind strial Science and Technolog ,705-1 Shimoimai mi, Ebina, Kanaga a 243-0435, Japan
2
Laborator for Materials and Str ct res, Tok o Instit te of Technolog ,4259 Nagats ta-cho, Midori, Yokohama, Kanaga a 226-8503, Japan3

Department of Applied Chemistr , Fac lt of Science and Engineering, Kindai Uni ersit ,3-4-1 Ko akae, Higashi-Osaka, Osaka 577-8502, Japan
4
Japan S nchrotron Radiation Research Instit te, SPring-8,
1-1-1 Koto, Sa o, H ogo 679-5198, Japan5
S nchrotron Radiation Research Center, National Instit tes for Q ant m andRadiological Science and Technolog , 1-1-1 Koto, Sa o, H ogo 679-5148, Japan
6

Department of Applied Ph sics, School of Ad anced Science and Engineering,
Waseda Uni ersit , 3-4-1 Ok bo, Shinj k -k , Tok o 169-8555, JapanBi and Pb ha e a niq e 6s0 and 6s2 electron config ration that creates charge degrees of
freedom. D e to the lack of this 6s1 electron config ration, a propert called alence skipper, Bi
takes 3+ and 5+ and Pb takes 2+ and 4+. In partic lar, for pero skite compo nds containing Bi or
Pb at the A site, the alence state changes according to the depth of the d-orbitals of the transition
metal ions corresponding to the order in the periodic table of the elements d e to the close
relationship bet een the 6s le el of Pb or Bi and the 3d le el of the 3d transition metal ions. Fore ample, for BiMO3, M= Cr, Mn, Fe, Co, the state is Bi3+M3+O3, hile BiNiO3 has a specificalence state of Bi3+0.5Bi5+0.5Ni2+O3. PbMO3 has Pb2+0.5Pb4+0.5MO3 for M= Ti and V,
Pb2+0.5Pb4+0.5M3+O3 for M= Cr and Fe, PbCoO3 has Pb2+0.25Pb4+0.75Co2+0.5Co3+0.5O3, PbNiO3 has
Pb4+Ni2+O3. In BiNiO3 and PbMO3 (M = Cr, Fe and
Bi 4f
Pb 4f
Co), Bi and Pb become charge disproportionated in02
the 6s and 6s states, and temperat re- andpress re-ind ced
eliminationofchargedisproportionation and charge transfer phasetransitions occ r. The alence of the transition metal
-170
-165
-160
-155
M is changed in this process, hich leads to niq e
Binding ene g (eV)properties s ch as metal-ins lator transition andnegati e thermal e pansion. In this st d , ee al ated the electronic states of these materials b
HAXPES, and the cr stal str ct re distortions
ca sed b these electronic states ere in estigatedb cr stal str ct re anal sis sing s nchrotron
150
145
140
135
radiation X-ra diffraction and local str ct re
Binding ene g (eV)anal sis sing atomic pair distrib tion f nction
Fig re. Bi4f and Pb 4f HAXPES spectra for BiMO3(PDF) obtained from s nchrotron radiation X-ra
(M= Ni and Fe) and PbMO3 (M= Ti, Cr, Fe, Co,
total scattering patterns.
3+

3+

Bi

PbNiO3

5+

Bi

Bi

5+

3+

Bi

PbCoO3Bi(a. .)

3+

BiNiO3

In en iIn en i(a. .)Bi

BiFeO3

PbFeO3Pb

2+

PbC O3

PbTiO3and Ni)

Reference
A ma, M.; Sakai, Y.; Nishik bo, T.; Mi maki, M.; Watan ki, T.; Mi oka a, T.; Oka, K.; Hojo, H.; Naka, M.
Dal on Transac ions 2018, 47 (5), 1371 137

4+

Pb

P13

Electronic States of FeGa Alloy Studied by Hard and Soft
X-ray Photoelectron Spectroscopy
Testuya Miyazaki1, Akinori Irizawa 1, Kei Mitsuhara1, Shun Fujieda2,and Shin Imada1
1

Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
2
Osaka University, Suita, 565-0871, Japan

FeGa alloys are one of the Fe-based magnetostrictive materials. These alloys have different
crystal structures such as disordered A2, ordered B2, and D0 structures depending on
temperature and composition. Magnetostriction is a phenomenon in which magnetization andelongation occurs in same time, it also called Joule effect. Large magnetostriction over 200 ppm
was obtained at room temperature in Fe-Ga bcc single crystal structure with a Ga concentration of
17 at% by Clark et al [1]. On the other hand, magnetization change when external force isapplied to the material. The phenomenon is inverse magnetostriction, also it called Villari effect.
Because of these phenomenon, FeGa alloys are expected to be applied in not only actuatormaterial but also Power generation device as magnetostrictive material.
In this research, we studied Fe82％Ga18％ single crystals by X-ray photoelectron spectrometer(PHI Quantes, Dual Scanning X-ray Photoelectron Microprobe) equipped with hard X-ray (CrK ) and soft X-ra (Al K ) monochromatized sources at SR Center, Ritsumeikan University.

References[1] A. E. Clark, J. B. Restorff, M. Wun-Fogle, T. A. Lograsso, D. L. Schlagel, IEEE Trans. Magn., 37 (2000) 3238.

P14

Electronic Structure of Covalent-Chain Antiferromagnets
TlFeX2 (X = S, Se) Studied by HAXPES
Tomoki Shinozuka1, Kenta Inoue1,2, Kenta Hamahara1,2, Norimasa Sasabe2,
YongGu Shim1, Kazuki Wakita3, Zakir Jahangirli4, Imameddin Amiraslanov4,
Akira Yasui2, Nazim Mamedov4, and Kojiro Mimura1,2
1

Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531, Japan
2
Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198, Japan
3
Faculty of Engineering, Chiba Institute of Technology, Narashino, Chiba 275-0016, Japan
4
Institute of Physics, Azerbaijan National Academy of Science, Baku 1143, Azerbaijan

Electronic structure of the covalent-chain antiferromagnets TlFeX2 (X = S, Se) [1-4], having a
monoclinic structure of space group C2/m, has been investigated by polarization dependent
HAXPES. The polarization dependent HAXPES experiments with incident photon energy (hν) of
7.05 keV were done at BL09XU of SPring-8. The samples were arranged so that infinite chains,
built along c-axis of FeX4 tetrahedra (β modification), are parallel (perpendicular) to the electricfield vector in the p- (s-) polarized configuration. Valence band HAXPES spectra show distinct
polarization dependence as shown in Fig. 1. For both compounds, the valence band spectra at thep-polarized configuration correspond to calculated density of state (DOS) except for slight
discrepancies around 5 eV, as is the result observed at hν = 6 keV [5]. These discrepancies
suggest the competition between localized and delocalized characters of Fe 3d electrons. On theday, we are planning to compare the spectra at s-polarized configuration with the calculated DOS
and to discuss about the Fe 3d state in TlFeX2 in detail.

Intensity (arb. units)p-pol.
s-pol.
TlFeS2

TlFeSe2105Binding Energy (eV)0Fig. 1: Polarization dependence of valence band HAXPES spectra for TlFeX2 (X = S, Se) taken at 300 K.

References[1] G. I. Makovetskii and E. I. Kasinskii, J. Inorg. Mater. 20, 1514 (1984).
[2] D. Welz, et al., J. Phys. Chem. Solids 50, 297 (1989).
[3] S. N. Mustafaeva, et al., Phys. Solid State 42, 2197 (2000).
[4] Z. Seidov, et al., Phys. Rev. B 65, 014433 (2001).
[5] K. Mimura, et al., Phys. Stat. Solidi C 10, 989 (2013).

P15

Electronic States of type-II Na-Ba-Si Clathrate Studied by
Hard X-Ray Photoelectron Spectroscopy
Yuchen Chen 1,2, Yuuki Shimada1,2, Taichi Usui1,2, Tetsuya Miyazaki1,2,
Syota Asai1,2, Masanori Shimamoto1,2, Goro Nozue2,3, Akane Ose2,3,
Hayato Hashizume2,3, Miwa Tsutsumi2,3, Kanji Miyazaki2,4,
Yuri Murakami2,4, Natsumi Tanaka 2,4, Yuina Kanai-Nakata1,2,
Hidenori Fujiwara2,3, Satoru Hamamoto2, Atsushi Higashiya2,5,
Atsushi Yamasaki2,4, Akira Sekiyama2,3, Ke ji Tama ak 2, Maki a Yaba hi2,Tea I hika a2, Haruhiko Morito6, and Shin Imada1,2
1
2

Ritsumeikan University,Shiga 525-8577, JapanRIKEN SPring-8 Center, Hyogo 679-5148, Japan
3
Osaka University,Osaka 560-8533, Japan
4
Konan University, Hyogo 658-8501, Japan
5
Setsunan University, Osaka 572-8508 , Japan
6
Tohoku University, Miyagi 980-8577, JapanThe Seebeck effect is the electromotive force that develops across two points of asemiconductor or metal when there is a temperature difference between them, which has been
applied to thermoelectric conversion. In order to improve the performance of thermoelectric
properties, the electrical resistivity and thermal conductivity must be reduced. A material thattransmits electricity well like crystals and does not transmit heat like glass would be ideal.
The Na16Ba8Si136 belongs to the type II clathrate. Its crystal structure consists of 16
dodecahedron and 8 hexakaidecahedron cages. The Ba and Na atoms occupy the 8b and 16c
sites in the cage, respectively. The atoms in the cage can move around inside the cage. Bymeasuring the core-level spectra of the three elements, the electronic states can be understood.
Experiments have been carried out at BL19LXU in SPring-8 using MBS A-1 analyzer.
Typically, there is only one peak per core-level, however, peak splitting was observed in the
core-level spectrum of the clathrate compound. The fact that the atoms inside the cage can movearound may be one of the reasons for the peak splitting. In order to know how the electronic
states of the material changes at different temperatures, we have also measured the core-level
spectra and the valence band spectra by x-ray photoelectron spectroscopy at 5K, 100K, 180K,
and 260K.

P16

Ir 5d State of CuIr2S4 Studied by Ir 2p3/2-5d Resonant
HAXPES
Yukihiro Taguchi1, Yoshinori Shibagaki1, Akira Yasui2, Norimasa Sasabe2,
Naomi Kawamura2, Eiji Ikenaga2,3, Masaichiro Mizumaki2, Satoshi Tsutsui2,
Hiroki Ishibashi4, and Kojiro Mimura1
1

Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531, Japan
2
Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198, Japan
3
Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya , Aichi 4648601, Japan
4
Department of Physical Science, Osaka Prefecture University, Sakai 599-8531, Japan

CuIr2S4 exhibits structural, metal-insulator, and paramagnetic-diamagnetic transitions around
226 K [1]. The Ir 5d state of CuIr2S4, which plays an important role in the transitions, has been
investigated by Ir 2p3/2-5d resonant HAXPES at 300 and 150 K. Figure 1 shows the on- (solid
curve) and off- (dotted) resonant valence-band (VB) photoemission spectra at 300 K along withdifference (open circles) between the two spectra. Resonant enhancement of the Ir 5d
photoemission is not so strong as was expected, possibly because of the itinerant nature of the Ir
5d state to some extent. Owing to the photoionization cross sections, however, the Ir 5d-derived
shoulder and peak are clearly observed at 0.5 and 1.6 eV, respectively, in contrast to the VB
spectrum taken with hn =1.3 keV [2]. The shoulder and the peak closely resemble those predicted
theoretically [2]. The Ir 5d state is redistributed by cooling below the transition temperature.
Change in the difference spectrum is observed around 3, 5.5, and 10.5 eV as indicated by arrows.

Fig. 1: On- (solid curve) and off- (dotted) resonant valence-band spectra of CuIr2S4 in the Ir 2p3/2-5d
absorption region around 11.2 keV. Open circles are difference between the two spectra multiplied by 5.

References[1] T. Furubayashi, T. Matsumoto, T. Hagino, and S. Nagata, J. Phys. Soc. Jpn. 63 3333 (1994).
[2] J. Matsuno, T. Mizokawa, A.Fujimori, D. A. Zatsepin, V. R. Galakhov, E. Z. Kurmaev, Y. Kato, and S. Nagata,Phys. Rev. B 55 R15979 (1997).

P17

Observation of electronic structure of Co2NbSn by hard x-ray
photoelectron spectroscopy
Yuuki Shimada1,2, Taichi Usui1,2, Tetsuya Miyazaki1,2 ,Yuchen Chen1,2, Syota Asai1,2, Masanori Shimamoto1,2 ,Goro Nozue2,3, Hayato Hashizume2,3, Akane Ose2,3, Miwa Tsutsumi2,3 ,Kanzi Miyazaki2,4, Yuri Murakami2,4, Natsumi Tanaka 2,4,
Yuina Nakata1,2, Hidenori Fujiwara2,3, Satoru Hamamoto2 ,Atsushi Higashiya2,5, Atsushi Yamasaki2,4, Akira Sekiyama2,3, Shin Imada1,2
1
2

Ritsumeikan University, Shiga 525-8577, JapanRIKEN Spring-8 Center, Hyogo 679-5148, Japan,
3
Osaka University, Osaka 560-8533, Japan,
4
Konan University, Hyogo 658-8501, Japan,
5
Setsunan University, Osaka 572-8508, Japan

Heusler alloys are typical ordered alloys with the molecular formula of X2YZ.
Co2NbSn exhibits a structural phase transition (martensite transition) that is closely related toshape memory alloys among Heusler alloys.
During the martensitic transition, various properties such as crystal structure, magnetic
properties, and electrical resistivity are changed.
The structural phase transition temperature and Curie temperature of Co2NbSn differ between
samples. The sample undergoes a structural phase transition from cubic to orthorhombic at 191K,
and from paramagnetic to ferromagnetic at 106K. Since Co2NbSn contains Sn as an impurity
phase, we focused on the Co inner shell.
In view of these two points, the present measurements were aimed at clarifying whether the Co2p
peak changes its spectrum with temperature by moving back and forth between 240 K and 150 K.
Also, Heusler alloys are generally itinerant electronic states. However, the 3d orbitals oftransition metals are also thought to be localized. Therefore, because of the 3d magnetic moment,
the 3s orbitals of the inner-shell electrons are observed as a multiplet splitting.
Therefore, the 3s orbitals were measured at 240K and 150K to confirm the multiplet splitting.
The measurements were carried out at BL-19LXU in Spring-8 using hard X-rays with an energyof 7900 eV.
As a result, the temperature dependence at 240 K and 150 K was confirmed.
However, the analysis of the multiplet structure of Co3s and the HAXPES-MCD analysis are stillin progress.
As for the temperature dependence, it is thought that the energy degeneracy was solved bychanging the structure. This is thought to be due to the band-Jahn-Teller effect.

P18

Trial of hard X-ray photoemission electron microscopy(HAXPEEM) at SPring-8
Satoru Hamamoto 1, Hidenori Fujiwara 2,1, Masaki Oura 1, Kenji Tamasaku 1,3,
Goro Nozue 2,1, Akira Sekiyama 2,1, Akinobu Yamaguchi 4,1 and Takuo Ohkochi3,1
1

RIKEN SPring-8 Center, 1-1-1, Kouto, Sayo, Hyogo 679-5148, Japan
Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531, Japan
3
Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo, Hyogo 679-5198, Japan
4
University of Hyogo, 3-1-2 Kouto, Kamigori, Hyogo 678-1205, Japan2

Photoemission microscopy with hard X-rays, HAXPEEM, is a promising method for real-spaceelectronic/magnetic states analysis of electronic devices under operation, due to its bulk-sensitivity.
We brought a PEEM apparatus (FOCUS PEEM with imaging energy filter) into the hard X-ray
beamline BL19LXU at SPring-8 and performed HAXPEEM observations, as a first feasibility test.
Figure 1 shows XAS- and XMCD-PEEM images and spectra of a Gd26Fe66Co8 thin film, whose
surface is irradiated by femtosecond laser pulses prior to the PEEM observations to create randommagnetic domains. To examine the bulk sensitivity, half area of the sample surface is capped with
100 nm-thick Au. The local XAS spectrum (Fig. 1 (a)), chemical contrast (Fig. 1 (b)) and XMCD
contrast (Fig. 1 (c)) at Gd L3-edge were clearly seen on the bare GdFeCo area. As for the area
capped by the Au, although the XAS spectra (Fig. 1 (a)) and XMCD contrast (Fig. 1 (c)) were
under detection limit, faint but noticeable chemical contrast (artificial ditches (dotted circles in Fig.
1 (b))) were found. In the presentation, we will discuss more detailed results as well as future
prospective of application to actual device research.

Fig. 1: HAXPEEM data at Gd L3-edge of GdFeCo thin film irradiated by femtosecond laser pulses. 100
nm-thick Au capping layer is deposited at the right half region of the field of view. (a) Area-selected
XAS spectra (b) Chemical mapping (c) XMCD-PEEM.

P19

Ground State Symmetry of Rare-earth Ions and Emission
Angle Dependence in Resonant X-ray Photoemission
Hisashi SOMA1, Yoshihito MATSUMOTO1, Takayuki UOZUMI1
1Osaka Prefecture Univ.

4f rare-earth compounds exhibit a variety of physical properties and have been widely studied
due to their interest in materials science. Core-level X-ray spectroscopy is a powerful technique
to investigate the electronic state of such strongly correlated electronic systems.
The purpose of this study is to clarify the relationship between the ground state (GS) symmetryof the rare-earth (RE) ions and the resonant X-ray photoemission (RXPS), by focusing on thedependence on both the incident photon polarization and the emission angle of photoelectrons.
This will provide us useful information for GS character of RE ions, including multipole states.
In this study, phase diagrams for RE ions under a weak cubic crystal field are systematicallycalculated, and the RXPS at the 2p→5d resonant excitation are calculated for each phase of
typical RE ions by considering the ionic full-multiplet interactions, especially paying attention on
the peak-intensity change around the azimuth angles of the sample surface. The figures show theresults for Er3+ ion, as an example, where the RXPS peak-intensity patterns for azimuth angle(right) are shown for each GS phase in the phase diagram (left) and for the sample surface
normals.
In the presentation, we also report the peak-intensity patterns calculated for resonant X-ray
emission spectroscopy (RXES) at the 2p→4f excitation, and the relationship between the GSsymmetry and the peak-intensity patterns of RXPS and RXES are discussed.
Γ1+
Γ3+

Γ3+

Γ5+

111

Γ5+
Γ1+

110

001

Fig. 1: Phase diagram for Pr3+ under cubic crystal field (left), and the RXPS peak-intensity patterns of
Er3+for azimuth angle around the sample surface normals.

P20Core-level x-ray photoemission spectroscopy of 3d transition
metal oxides: DFT+DMFT analysis
Keisuke Higashi1, Tatsuya Yamaguchi1, Winder Mathias2,
Takayuki Uozumi1, Jan Kuneš2, and Atsushi Hariki1
1

Department of Physics and Electronics, Osaka Prefecture University, Sakai, Osaka 599-8531,
Japan
2

Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
HIGASHI, WINDER, KUNEŠ, and HARIKI
Supplemental Material [54], reveal that for optimal Δdp

Core-level hard x-ray photoemission spectroscopy (HAXPES)a powerful
toandstudy
doped holes areis
almostequally sharedprobe
by Ni, Nd,
O sites.
This isIna remarkabledifference to monovalentcuprates
electronic properties of 3d transition-metal oxides (TMOs).
TM 2p HAXPES,a 2p coreholeordivalent NiO. In these systems of strong charge-transfer
created by x-rays lowers the 3d level energies on the excitedsitetheviadoped
the holes
electron-holeinteraction,
character,
reside predominantly
in O 2p
orbitals,irrespective
a substantial
3d spectral
weightleading an electron charge transfer (CT) from surrounding
ions
to theofempty
d states.
Besidesjust below the Fermi level [60]. Moreover, for the optimal
local screening from nearest-neighboring ligands, nonlocal
screening
(NLS)
from
other
TM
sites
Δdp values inferred above, the doped holes in NdNiO2
affects the core-level line shape [1,2]. The NLS often provides
richtheinformationon (Fig.
the electronic
do not enterNi 3z2 − r2 orbitals
4). The singledescriptionis, thus, valid
not only for theproperties of 3d TMOs, such as metal-insulator transitionband
andHubbard
long-range
magneticordering.
parent NdNiO2 but also for the superconducting one
We study the NLS effect in a series of 3d TMOs using
a computational method based on
Nd0.8 Sr0.2 NiO2 , as suggested by Refs. [35–37].
density functional theory (DFT) combined with dynamical
mean-field
theory(DMFT),
whichby
Proximityof NiO2 layers
to a Mott
state (precluded
self-doping
fromvalenceNd) suggests
a superexchange
was introduced recently [2,3]. This method describes both
realistic
bandsthatwitha strong
interaction still plays a role despite the metallic state.
electronic correlation and the local electron-hole interactionin the HAXPES
Using(core-holethe optimal Δpotential)
dp , we arrive [54] at the nearest Ni-Ni
antiferromagnetic
in the rangehybridization
40–60 meV. Given
process. Thus, it allows us to model the core-level spectra
consideringexchange
long-distantthe oversimplificationof representing spin response of aeffect, beyond a conventional impurity model using e.g., MO
6 cluster model.
metal in terms of local moments interactions, this value is
We analyze experimental data in early to late TMOs, paying
the NLSeffect:1) forconsistentattention
with 69 meVto
inferredfrom theRIXS experimenton a related compound
La4 Ni3 O8 NLS[61]. is present,
NdNiO2, a mother compound of recently-discovered superconducting
nickelate,see figure, and can be used to determine the key model
parameters [4], 2) for Sr2FeMoO6 and LaFeO3, Fe 2p(a)
NLS features, reported recently [5], are closely related tothe pattern of the magnetic ordering, and 3) SrTiO3 andTiO2, even for trivalent Ti (3d0), a long-distant electron
hopping is needed to reproduce the CT excitations in
the HAXPES spectra. This study indicates that the NLS
effect is important for the interpretation of core-level
HAXPES in a series of 3d TMOs.

The calculate
behavior to Nd

B

As expected
the experimenta
peak correspon
2p3=2 to an em
main peak is ac
hybridization w
Fig. 5(b) reprod
however, the weto draw conclus
The RIXS schanges with th
all Δdp values cconstant Eloss ir
Ein ) at Eloss ∼(Eloss linearly ifrom t2g → x2
reflects a rapid
ing Δdp , the RL
upward shift toFig. 2(b)], whil
vicinity of the F
spectra with inc
part, the onset(a)References(b)[1] M. A. van Veenendaal and G. A. Sawatzky, Phys. Rev. Lett. 70, 2459 (1993).
[2] A. Hariki, T. Uozumi, and J. Kuneš, Phys. Rev. B 96, 045111 (2017).
[3] A. Hariki, M. Winder, and J. Kuneš, Phys. Rev. Lett 121, 126403 (2018).
[4] K. Higashi, M. Winder, J. Kuneš, and A. Hariki, Phys. Rev. X 11, 041009 (2021).
[5] D. Phuyal, S. Mukherjee, S. K. Panda, G. J. Man, K. Simonov, L. Simonelli, S. M. Butorin, H. Rensmo, and O.
Karis, J. Phys. Chem. C 125, 11249 (2021).

FIG. 5. (a) Ni 2p3=2 XPS spectra and (b) Ni 2p3=2 XAS spectraof NdNiO2 calculated by the LDA þ DMFT method for different
Δdp values. The experimental data [9,12] are shown together. For
comparison, experimental Cu 2p3=2 XPS data of La2 CuO4 areshown (gray) [19]. The spectral broadening is taken into accountusing a Lorentzian 300 meV (HWHM) and a Gaussian 250 meV(HWHM) for XAS and a Lorentzian 500 meV and a Gaussian
400 meV for XPS. The XPS spectra with different broadening(b)

FIG. 6. (a) Ni 2
of LaNiO2 calcul
Δdp values. The s
Lorentzian 300(HWHM) for XA

P21

Design of an in-situ, in-operando HAXPES cell for thecharacterization of SEI formation in Li-ion batteries
Federico Giovanni Capone1,3, Jonas Sottman 1,3, Jean-Pascal Rueff 2, and Alexis
Grimaud3
1

PHENIX Lab, Sorbonne Université, CNRS UMR 8234, 75252, Paris, France
SOLEIL Synchrotron, L Orme des Merisiers, BP48 Saint Aubin, 91192 Gif sur Yvette3
Réseau sur le Stockage Electrochimique de l'Energie (RS2E), CNRS FR 3459, 33 rue Saint Leu,
Amiens Cedex 80039, France
2

Lithium ion batteries (LIBs) have gain tremendous importance recently as a stable energy storage
system [1]. During the first cycles, a thin layer is formed on the electrode due to the reduction of
the electrolyte components at the anode. This Solid Electrolyte Interface (SEI) leads to an initial
capacity loss but also prevents degradation of the battery [2] and help to improve life expectancy
and safety [3]. XPS is a very powerful technique for studying the SEI, but its surface sensibility
limit the access to the SEI [4]. HAXPES appears as a powerful alternative to XPS to obtainreliable in-operando, in-situ depth profiling: thanks to the high kinetic energy electrons, it ispossible to probe up to several tenths of nm into the SEI depth [5].

Here, we will present a new compact cell to perform in-situ
operando HAXPES for batteries materials. In standard ex situ
XPS, electrodes are removed from the battery and must be
rinsed from the excess of electrolyte. Moreover, ex situ
characterization may miss some phenomena related tometastable species. The cell design is inspired bydevelopments in electrocatalysis [6]. In this new cell (Fig.1)
SEI will be probed through a nanometer-thick membrane,
supported on a silicon nitride membrane. The thin membrane
Fig. 1 : schematic design of theseparates the liquid electrolyte from the UHV while being
in-operando cell [7]partly transparent to the outgoing HAXPES photoelectrons.
The cell can fit onto a standard sample plate compatible with usual sample transfer system. The
cell is currently under fabrication and will be tested shortly at the GALAXIES beamline at
SOLEIL. We believe the new cell will provide new insights into the SEI formation mechanism
and batteries interfaces [7] allowing to study a system very close to the real one in-operando.
References[1] Gröger, O.et al.(2015). Journal of The Electrochemical Society, 162(14), A2605.
[2] Peled, E., et al. (1995). MRS Online Proceedings Library Archive, 393.
[3] Gauthier, M., et al. (2015). The journal of physical chemistry letters, 6(22), 4653-4672.
[4] Edström, K.,et. al. (2006). Journal of Power Sources, 153(2), 380-384.
[5] Nordh, T. et al. (2016). The Journal of Physical Chemistry C, 120(6), 3206-3213.
[6] V a c V, J. J., et al.. (2015). Angewandte Chemie International Edition, 54(48), 14554-14558.
[7] Atkins, D., et al. (2021). Advanced Energy Materials, 2102687.

P22

APXPS study on Pt3Pd3Sn2/C catalyst for dimethyl etheroxidation
Michal Prochazka1, Palaniappan Subramanian1, Sunil Wilfred D'Souza1, Sarath
Sasi1, Slavomir Nemsak2, Alex Schechter3, Bongjin Simon Mun 4, Jan Minar1
1

New Technologies, Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Plzen,
Czech Republic
2

Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley,
CA 94720, USA
3

4

Department of Chemical Sciences, Ariel University, P.O. Box 3, Ariel, 44837, Israel
Department of Physics and Photon Science, Gwangju Institute of Science and Technology,
Gwangju, 61005, Republic of Korea

Recently, direct methanol fuel cells, have drawn lots of attention from researchers due to theirpotential applications with a target to replace lithium batteries. In this work we focused on fuelcells using dimethyl ether (DME) oxidation reaction on platinum and its alloys such as PtPdSn,
which shows higher specific power density. DME has several advantages over other fuels,
including high energy density, pumpless fuel delivery, liquefied storage, or low toxicity. Becauseof the possible near-surface effects occurring in the catalysts during activation or operation we
investigated the materials using various surface techniques such as ambient pressure X-ray
photoelectron spectroscopy (APXPS) or X-ray absorption spectroscopy (XAS) which help us
provide valuable information about the role of each element in the reaction mechanism of DME
oxidation.
In our experiments Pt3Pd3Sn2/C nanoparticles were synthesized and drop casted on carbon fiber
paper and silicon substrates. The oxidation states and binding energies of each element were thenstudied in various environment such as H2, DME or DME + H2O.

P23First HAXPES Studies of Photovoltaic Materials at EMIL:
Depth-Resolved Structure of (Ag,Cu)(In,Ga)Se2
Donald Valenta,1 Jakob Bombsch,1 Regan G. Wilks,1,2 Natalia Martin,3 Tobias
Törndahl,3 Marika Edoff,3 Mihaela Gorgoi,1,2 Anna Efimenko,1,2 Andreas Gaupp,1,2
and Marcus Bär1,2,4,5
1Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin,

Germany

2Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien

und Energie GmbH, Berlin, Germany

3Division of Solar Cell Technology, Department of Materials Science and Engineering, Uppsala

University, Uppsala, Sweden
4Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, Berlin, Germany
5Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg,
Erlangen, Germany

The Energy Materials In-situ Lab Berlin (EMIL) is a joint facility of the Helmholtz-Zentrum
Berlin (HZB) and the Fritz-Haber Institute of the Max Planck Society (FHI). The HZB operates alarge-scale interconnected UHV system dedicated to the study of energy materials and devices.
This system connects deposition and treatment chambers to advanced analytics, which include twolab-based photoemission systems in addition to a dual-color, wide-energy-range (80 eV-10 keV)beamline and an X-ray spectroscopy endstation, providing for multiple measurement techniques,
ser ing as a ma erials science ool ches .
This contribution will illustrate the capabilities of the system by focusing on an depth-dependent
photoemission study of (Ag,Cu)(In,Ga)Se2 thin-film solar cell absorbers. Such chalcopyrite
materials traditionally Cu(In,Ga)(S,Se)2 have a bandgap which can be tuned by varying the
stoichiometry of the film. Alloying Cu(In,Ga)Se2 with Ag to produce (Ag,Cu)(In,Ga)Se2 canadditionally reduce structural defects and improve opto-electronic properties, as well as provide af r her means of ning he film s proper ies. This flexibility makes them extremely useful as lightabsorbing layers for solar cells, as it allows controlled variation of electronic properties throughout
the thickness of the thin (on the order of 1-2 µm) layer, optimizing charge carrier creation andextraction. While the composition variation on this depth scale can be coarsely determined bydestructive methods (e.g., secondary ion mass spectrometry), the near-surface (i.e., uppermost 10s
of nm) region of the absorbers also shows considerable changes in composition and properties. The
nature of this region can strongly influence the operating parameters of the resulting solar cell,because it ultimately forms the interface with the transparent front contact (generally via an
additional buffer layer) and thus can impede charge carrier extraction if not designed carefully. In
this contribution, we use the wide range of excitation energies at EMIL to probe this critical nearsurface region of the (Ag,Cu)(In,Ga)Se2 absorber to understand the relationship between Agalloying, Cu-deficiency, and electronic structure tuning of the film, with the goal of establishing a
structure-function relationship within the system.

P24

HZB Energy Materials Research at SPring-8 BL15XU 20182019
Regan Wilks1,2, Shigenori Ueda3,4,5, and Marcus Bär1,2,6,7
1

2

3Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin,
Germany

Energy Materials In-Situ Laboratory Berlin (EMIL), Helmholtz-Zentrum Berlin für Materialien
und Energie GmbH, Berlin, Germany

Synchrotron X- a S a

a SP

8, Na

a I
Japan

ef

Ma e a Sc e ce (NIMS), H,

4

Research Center for Functional Materials, NIMS, Tsukuba, Japan
Research Center for Advanced Measurement and Characterization, NIMS, Tsukuba, Japan
6
Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, Berlin, Germany
7
Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg,
Erlangen, Germany
5

For several years, the Department of Interface Design at Helmholtz-Zentrum Berlin fürMaterialien und Energie GmbH performed beamtime at the NIMS contract beamline BL15XU [1]
at SPring-8, obtained through partnerships and through the Na ec
Paf:
Microstructure Characterization P a f(Nano-PF) [2], to study a number of energy-relatedmaterials systems.
These studies of materials from photovoltaics, batteries, fuel cells, etc. have played crucial rolesin the research efforts of the group and have contributed to numerous PhD theses, conference
presentations, and joint publications. In light of the recent decommissioning of this beamline, wewill present an overview of this energy-related materials research, highlighting some of the mostimportant findings, with a focus on the study of buried interfaces as well as on theelectronic/chemical structure of thin-film photovoltaic materials.
References[1] S. Ueda, Y. Katsuya, M. Tanaka, H. Yoshikawa, Y. Yamashita, S. Ishimaru, Y. Matsushita, and K. Kobayashi, AIP
Conf. Proc. 1234, 403 (2010).
[2] https://www.nims.go.jp/nmcp

P25

X-ray spectroscopic study ofthe electronic states of Pd nanoparticles
Satoshi Ogawa1, Chie Tsukada 2, Akira Yasui 3, Akitaka Yoshigoe 4,
Eiji Ikenaga 1,5, and Shinya Yagi 1,5
1

Department of Energy Engineering, Graduate School of Engineering, Nagoya University, Japan
2
Aichi Synchrotron Radiation Center, Aichi Science & Technology Foundtion, Japan
3
Japan Synchrotron Radiation Research Institute (JASRI) , Japan
4
Japan Atomic Energy Agency (JAEA) , Japan
5
Institute of Materials and Systems for Sustainability (IMaSS) , Nagoya University, Japan

Palladium nanoparticles (Pd NPs) are attractive material in many scientific and industrial fields.
The remarkable point is the difference from the bulk one such as high catalytic activity andanomalous hydrogen storage property [1]. It seems that these properties originate from theelectronic states around Fermi level, but specifics still unknown. In this study, we haveinvestigated the electronic state of Pd NPs by soft and hard X-ray spectroscopies. Soft and hard
X-ray photoelectron spectroscopy (SXPS and HAXPES) reveals the electronic state of Pd NPs atlateral surface and inside of the NPs, respectively. Moreover, near edge X-ray absorption finestructure (NEXAFS) of Pd NPs has been observed to clarify the unoccupied electronic states.
Pd NPs were fabricated by the gas evaporation
method using inert He gas [2]. The Pd NPs possess theclean surfaces because any surfactants or polymers havenot been used during the fabrication process. SXPS andHAXPES have been done at BL23SU and BL47XU in
SPring-8, respectively. Pd L3-edge NEXAFS was
measured at BL6N1 in Aichi SR. All samples were
fabricated and transferred without exposure to the air toavoid the surface oxidation.
Fig. 1 shows valence band (VB) spectra of Pd NPs
and Pd bulk obtained by HAXPES. DOS calculated
based on DFT are also shown in Fig. 1. The DOS of Pd
bulk represent sufficiently the feature of VB spectrum of
Pd bulk. The shape of the VB of Pd NPs is different
from that of Pd bulk. This difference originates from thehuge specific surface area of NPs. The features of Pd
NPs are similar to DOS of Pd(111) lateral surface.
Fig. 1: Valence band spectra of Pd NPs
References[1] M. Yamauchi et al., J. Phys. Chem. C 112, 3294 (2008).
[2] S. Ogawa et al., e-J. Surf. Sci. Nanotech. 13, 343 (2015).
[3] K. Schwarz et al., Comput. Mater. Sci. 28, 259 (2003).
[4] K. Soda et al., J. Phys. Soc. Jpn. 60, 3059 (1991).

and Pd bulk obtained by HAXPES.
Back ground has been removed by
iteration method [4]. DOS of Pd(111)and Pd crystal are also shown.

P26
Spectroscopic study and photocatalytic activity of Au-Ni
nanoparticles for hydrogen production reaction by water splitting
Takumi Kawaguchi1, Satoshi Ogawa1, Shinya Yagi1,2, Akira Yasui3 andEiji Ikenaga1,2
1

2

Department of Energy Engineering, Graduate School of Engineering,
Nagoya University, Japan

Institute of Materials and Systems for Sustainability, Nagoya University, Japan
3
Japan Synchrotron Radiation Research Institute

Au-Ni nanoparticles are remarkable co-catalysts for photocatalytic reactions of hydrogenproduction by water splitting [1]. However, it is difficult to prepare Au-Ni well-mixed
nanocomposites via wet chemical method because of their immiscibility. In this research, AuNi nanoparticles were prepared by solution plasma process which is suitable for rapid coevaporation and aggregation (1 μs order) of Ni and Au atoms. The composition of Au and Ni
were determined by the combination of Energy Dispersive X-ray Spectroscopy and ScanningElectron Spectroscopy. Soft X-ray photoelectron spectroscopy (SXPS) was performed forsurface analysis of Au-Ni nanoparticles and hard X-ray photoelectron spectroscopy (HAXPES)in SPring-8 BL09XU was performed for analysis of inside of Au-Ni nanoparticles.
Fig. 1A shows Au 4f SXPS spectra of Au-Ni nanoparticles. As Ni composition increased, thepeak component appears on the lower binding energy side compared with metallic component
at 84 eV. Moreover, from Ni 2p SXPS spectra of Au-Ni nanoparticles (not shown here), it isfound that Ni(OH)2 state is dominant on the surface of Au-Ni nanoparticles. Fig. 1B shows Au
4f HAXPES spectra of Au-Ni nanoparticles. These results indicate that metallic Au exists insideof Au-Ni nanoparticles. Fig. 1C shows Ni 2p HAXPES spectra of Au-Ni nanoparticles. NiO
and Ni(OH)2 components increased as Ni composition increased. However, those components
decrease after Au0.26Ni0.74. It is also found that, Ni0 state exists in all samples. From above
results, it is suggested that the Au-Ni nanoparticles have the core-shell structures as shown in
Fig. 1D (Au rich condition) and Fig. 1E (Ni rich condition).
(A)

(B)

(C)

rich
(D) Aucondition

rich(E) Nicondition

Fig. 1. SXPS spectra of Au 4f (A) and HAXPES spectra of Au 4f (B) and Ni 2p (C).The suggested
structure of the nanoparticles is shown as (D), (E).
Reference[1] A. Luna et al., Appl. Catal. B: Environ. 191, 18 (2016).

P27

The “Two-Color” EMIL Beamline at the
BESSY II Light Source
Mihaela Gorgoi 1,2, Stefan Hendel 2,3, Franz Schäfers 2,3, Andreas Gaupp 2,3,
Michael Hävecker 2,4,5, Simone Vadilonga 2,3, Jens Viefhaus 2,3,
Simone Raoux 2,6,7, Marcus Bär 1,2,8,9
1
2Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB),
Albert-Einstein-Str. 15, 12489 Berlin, Germany

Energy Materials In-situ Laboratory Berlin (EMIL), HZB, Albert-Einstein-Str. 15, 12489
Berlin, Germany
3

4

Optics and Beamlines, HZB, Albert-Einstein-Str. 15, 12489 Berlin, Germany
Fritz-Haber-Institut, Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
5
Max-Planck-Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470
Mülheim an der Ruhr, Germany
6

7

Nanospectroscopy, HZB, Albert-Einstein-Str. 15, 12489 Berlin, Germany
Physics Department, Humboldt University Berlin, Newtonstraße 15, 12489 Berlin, Germany
8
Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (HI ERN),
Albert-Einstein-Str. 15, 12489 Berlin, Germany
9

Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität ErlangenNürnberg, Egerlandstr. 3, 91058 Erlangen, Germany

The Energy Material In-situ Laboratory Berlin (EMIL), a joint project of the HZB, the FritzHaber Institute of the Max-Planck Society and the MPI for Chemical Energy Conversion, is aunique infrastructure that focuses on the study of energy conversion, efficiency, and storage
materials by combining industry-scale sample production facilities and various spectroscopic
and microscopic techniques that fully exploit the 80 eV to 10 keV “two-color” beamline. EMIL
is a state-of-the-art surface and interface analysis laboratory that provides access to a large
variety of synchrotron methods PES, HAXPES, XAS, XES, RIXS, XRF, and STXM with thephotoemission and photon-in-photon-out techniques being operable under near-ambient or trueatmospheric pressure conditions, respectively. The wide range of photon energies provides
access to surface and (buried) interface chemical and electronic structures with information
depths from a few Å to several µm.
The “two-color” EMIL beamline at BESSY II combines two undulator branchlines delivering
soft and hard X-rays. The soft X-ray UE48 and the hard X-ray in-vacuum cryo-undulator U17
are providing high brilliance across a continuous energy range between 80 eV and 10 keV. The
branchlines are designed to focus the radiation at the same spatial point in any of the three endstations SISSY-I, SISSY-II, and CAT. Two other foci, one soft and one hard, are available to
STXM and PINK end-stations, respectively. The branchlines can be operated alternatively
providing X-rays to either the same analytics system or simultaneously to different analysis
chambers. The EMIL beamline system contains 26 optical elements and three monochromators(two PGM and one DCM) all installed in an area of 2 meters width and 65 meters length.
With both, the UE48 soft X-ray and U17 hard X-ray branches now in full user operation, in
this contribution, we will give a detailed update of the status and performance of the EMIL
beamline(s). We will report on energy resolution, photon flux, and focus size as key
performance indicators.

P28

Effects of Sample-Aperture Cone Distance on
Environmental Charge Compensation in Hard X-ray
Photoelectron Spectroscopy
Kento Takenaka1, Koji Takahara2, Hirosuke Sumida3, and Satoru Suzuki 2
1Graduate School of Science, University of Hyogo, 3-2-1, Koto, Kamigori, Ako, Hyogo 6781297, Japan2

LASTI, University of Hyogo, 3-1-2, Koto, Kamigori, Ako, Hyogo 678-1205, Japan
3
Mazda Motor Corp., 3-1 Shinchi, Fuchu, Aki, Hiroshima 730-8670, Japan

One major problem of photoelectron spectroscopy is the charging effect in measuring bulk
insulator samples. It is known that the charging effect is reduced to some extent by introducing a
gas into an analysis chamber up to a500 Pa (environmental charge compensation) [1]. Here, we
demonstrate almost complete charge compensation by gas introduction into a near-ambientpressure hard X-ray photoelectron spectroscopy (NAP-HAXPES) apparatus at BL24XU, SPring8, equipped with a HiPP-2 electron energy analyzer (Scienta Omicron). The charging of a glass
slide (thickness: 1 mm) was successfully compensated by introducing nitrogen gas up to apressure of 2500 Pa at the sample-aperture cone distance d (Fig. 2, inset) of 0.3 mm (our normal
geometry), as shown in Fig. 1. More interestingly, the pressure required for charge compensation
was found to strongly depend on d, as shown in Fig. 2. At d=2.1 mm, the charging wascompensated at only 250 Pa. Possible reasons for the strong d dependence will be discussed.
2500

sample2000

Pressure (Pa)Intensity (arb.units)

3500Pa
3000Pa2500Pa2000Pa
1500Pa1000Pa
500Pa
0Pa

cone

1500

d

1000
500
0

1870

1860

1850

1840

Binding Energy (eV)Fig. 1: Si 1s spectra of a glass plate undervarious nitrogen pressures obtained at d=0.3
mm.

0.5

1.0
1.5
d (mm)

2.0

Fig. 2: Relationship between d and thepressure required for charge compensation.
The inset shows the definition of d.

References[1] EnviroTM, https://www.specs-group.com/nc/enviro/products/detail/enviroesca/

P29

Hard X-ray Photoelectron Spectroscopy Beamline Designed
at Shenzhen Innovation Light-source Facility (SILF)
Tianhui Liu1, Chunzhen Yang1, Yitao Cui1, and Ulf O. Karlsson1
1

Institute of Advanced Science Facilities, Shenzhen, China

Shenzhen Innovation Light-source Facility (SILF) is a newly proposed fourth-generationsynchrotron light source located in Shenzhen, China. It is currently in the planning stage and will
be constructed by the Institute of Advanced Science Facilities, Shenzhen (IASF). A 3 GeV
diffraction-limited storage ring with a circumference of 696 m has been designed for a low
emittance of <100 pm·rad and a beam current of 200-300 mA. Thus, a brilliant light source with abrightness in the order of 1021 phs/sec/mm2/mrad2/0.1BW will be built. This new synchrotron
light source will provide an innovative research platform for scientists and industries in China's
Greater Bay Area and even from around the world.
We will introduce the current progress of our light source facility, as well as the design of a highflux undulator beamline for HAXPES. This beamline is equipped with a double-crystal
monochromator, a high harmonics suppression mirror and Kirkpatrick–Baez mirror pairs,
providing 3.4-18 keV hard X-ray with a focused spot size of 15μm2. It will be dedicated to highenergy resolution fluorescence detected X-ray absorption spectroscopy (HERFD-XAS), X-ray
Emission Spectroscopy (XES), resonant inelastic X-ray scattering (RIXS) and hard X-ray
photoelectron spectroscopy (HAXPES) measurements for advanced materials research.

Fig. 1: An architect’s illustration of the Shenzhen Innovation Light-source Facility.

P30

Three-Dimensional Spatial-Resolved HAXPES Measurement
using a 1 m Focused Beam
Yasumasa Takagi1, Akira Yasui1, Taito Osaka2, Michihiro Sugahara2,
Naomi Kawamura1, Yasunori Senba1,2, Hiroshi Yamazaki1,2, Takahisa Koyama1,2,
Hirokatsu Yumoto1,2, Haruhiko Ohashi1,2, Yusuke Tamenori1 and Makina Yabashi1,21Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
2
RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan

BL09XU at SPring-8 has been upgraded as a beamline dedicated for hard X-ray photoelectron
spectroscopy (HAXPES) experiments in 2021. The HAXPES system with a wide-acceptanceangle (±32°) analyzer [1], which had been installed at BL47XU, was moved to the experimental
hutch (EH) 2. One of the key issues in the upgrade was the introduction of the Si 311/Si 220
double channel-cut monochromator, which provides a more intense beam than that of BL47XU
with a channel-cut monochromator with Si 444 reflection. Furthermore, a long Kirkpatrick-Baez(KB) mirror at EH 2 significantly reduced the beam loss compared to that with a short KB mirror
at BL47XU. These improvements enabled us to increase the intensity of the incident beam, and to
reduce the beam size by limiting a front-end slit aperture. The flux with a focused beam size of
1.5 (V) × 1 (H) µm2 at BL09XU is 1.5 times larger than that with a size of 1(V) × 4 (H) µm2 at
BL47XU. By combining the 1 µm focused beam and an angle-resolved measurement with awide-acceptance-angle analyzer, we were able to investigate the depth-dependent chemical statesin a local region. We performed selective depth-resolved HAXPES measurements on a sample ofAu patches of various sizes on a SiO2 substrate.
Figure 1 shows two-dimensional photoelectron intensity distributions for Au 4f and Si 1s
photoelectron, which were obtained by scanning the sample. We found that the distribution of Au
and Si was clearly resolved in thetwo-dimensional maps. In addition,
we performed HAXPES analysis toa local area by irradiating the beam
only onto a 10 µm square SiO2
region, and confirmed complete
suppression of the Au signal fromthis region. By depth-resolved
HAXPES
measurement,
thethickness of the SiO2 film in theregion was estimated to be about 1 Fig. 1: Two-dimensional photoelectron intensity distribution
images of Au patches on SiO2 acquired with Au 4f (left) and Si
nm
1s (right). 50 × 50 µm2

References[1] E. Ikenaga et al., Synchrotron Radiation News, 31, 10 (2018)

P31

The Operande Measurement for Bias Applied TechniqueUsing Laboratory Based Hard X-ray Photoelectron
Spectroscopy with GaKD X-ray Source
Tappei Nishihara1, Masatake Machida2, and Atsuhi Ogura1, 3
1

Meiji University, 1-1-1 Higashi-mita, Tama-ku, Kawasaki, Kanagawa, Japan, 214-8571
2
ScientaOmicron Inc., 6-17-10, Minamiooi, Shinagawa-ku, Tokyo, Japan, 140-0013
3
MREL, 1-1-1 Higashi-mita, Tama-ku, Kawasaki, Kanagawa, Japan, 214-8571

The performance of LSI devices is improving rapidly, and the progress is being made every day
toward the realization of the IoT society. In particular, the interface is the key to the performanceof the LSI devices [1, 2]. To evaluate the interfacial state, capacitance-voltage (C-V)
measurements are used electrically, photoelectron spectroscopy (XPS, HAXPES) using soft andhard X-rays is used for chemical bonding states, and transmission electron microscopy (TEM) is
used to evaluate the physical structure, respectively. In addition to the above evaluation
techniques, knowledge of the carrier behavior and the electronic states at the interface during
device operation is key to further improving performance. Therefore, HAXPES with appliedbias has been attracting attention as a method to evaluate the interface state during bias operation.
In this paper, we report the results of bias applied HAXPES measurements using the
HAXPES_Lab. [3].
In this experiment, we deposited TiN and ZrO2 films on Si substrates at 20 and 4 nm,
respectively. The applied voltages on the sample back surface were in the range of ± 2 V, while
the sample front surface was grounded. We measured Si 1s, Ti 1s, Ti 2p, O 1s and Zr 3p corelevel photoelectron spectra, respectively.
Figure 1 shows the dependence of the binding energy values of the Si-Si and Ti-N chemical bondson the applied voltage, calculated from the Si 1s and Ti 2p spectra. The Si-Si bond originating fromthe Si substrate was found to vary linearly with the applied voltage, with a slope of 0.46 calculated
by linear approximation. This indicates that the voltage
drop occurs not only at the TiN/Si interface but also inside
the TiN and ZrO2 films. The Ti-N chemical bond showed
an arc-shaped behavior against applied bias. This result
suggests the possibility of carrier trapping at the TiN/Si
interface and the TiN film defects. HAXPES_Lab. was
successfully used for the measurement of the operandmeasure with applied voltage, and the behavior of the near
the interface and in the film was successfully clarified.
This work was partially supported by NEDO.
Fig. 1 Si-Si and Ti-N binding energy
Refe ence [1] T. Na a e a ., ECS T a . 98, 113 (2020). [2] T.
dependence on the applied bias.
Dashed line shows the binding
energy shift equal to the applied bias.

Wa a abe e a ., Je a . Re . Sc . I. J. A . P . 55, 03DD12 (2016). [3] A. Reg. 89, 073105 (2018).

P32

Study on the Relationship between Chemical Structure andFunction of Amphiphilic Gel Surface
Eri Ito1, 2, Tatsuya Imai 2, and Katsuhiro Yamamoto2
1
2

Menicon Co., Ltd. 3-21-19 Aoi, Naka-ku, Nagoya 460-0006, JAPAN

Grad. Sch. of Eng. Nagoya Institute of Technology, Gokiso, Showa-ku Nagoya 466-8555, JAPANMore than 60 years have passed since gel materials were first utilized in soft contact lensmaterials. The current mainstream material is Silicone Hydrogel (SiHy)[1].
SiHy, which uses silicone compounds, has higher oxygen permeability and poorer
biocompatibility than general gel material. Therefore, various surface hydrophilization
approaches have been tried on SiHy[2], but the mechanism of functional change has not been fully
explained. In this study, we attempted to explain the surface chemical structure and functionalchange of SiHy by analyzing the difference between SiHy before and after plasma treatment
utilizing hard X-ray photoelectron spectroscopy (HAXPES) and neutron reflectometry (NR).
From the NR measurements, the changes in the scattering length density (SLD) profile before
and after the surface treatment and with the change in humidity environment are shown in Fig 1.
The surface treatment decreased the film thickness by about 20 nm and increased the SLD by
about 15 nm near the surface in the dry sample. These results suggested the etching of theelements from the surface, especially removing the atoms having smaller values of SLD (In thiscase, removal of the CH3 groups plausibly happened). Furthermore, the SLD near the surface
increased with raising humidity (D2O), indicating the process of D2O absorption by the SiHy.
In addition, the chemical shift of Si1s after hydrophilic treatment was observed from themeasurement of Si1s by HAXPES shown in Fig. 2. The chemical shift of Si1s (oxidation) strongly
occurred in the surface layer of 20 nm, which corresponded to the depth where the change in the
SLD was especially pronounced in the NR measurement.
This study can explain the relationship between the surface chemical structure and the water
absorption of SiHy due to the surface treatment by utilizing HAXPES and NR. The
complementary use of HAXPES and NR techniques is valuable and powerful to elucidate themicroscopic changes (chemical and functional) in the SiHy surface.

Figure1 The behaviour of SLD before and after surface treatment for SiHy
and the behaviour of SLD with change of water absorption state due tohumidity environment by neutron reflectometry

References[1] K. Yamamoto, Macromolecular Symposia 385, 18100181, (2019)[2] E. Ito Journal of Japan Contact Lens Society58, No.2 116-124(2016)

Fig.1 The chemical shift of Si 1s spectra on SiHy before
and after surface treatment observed by HAXPESPaticipants List
First Name

Last Name

Affiliation

Peter

Amann

Scienta Omicron

MarcusBär

Elin
Deepnarayan
Sara

Berggren
BiswasBlomberg

Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH
Uppsala University
Diamond Light Source
Lund University

Federico Giovanni
Hsun-Yun
YuchenRalph

CaponeChang
Chen
Claessen

CNRS & Sorbonne University
ULVAC-PHI, Inc
Ritsumeikan University
Universität Würzburg

Pierre-Marie
Wolfgang
Sunil Wilfred

Deleuze
Drube
DSouza

CEA-Leti
Deutsches Elektronen-Synchrotron DESY
University of West Bohemia

Hidenori
Ayumi

Fujiwara
Furukawa

Osaka University
RIKEN SPring-8 Center

Faris
MihaelaAlexander

Gelmukhanov KTH, Royal Insitute of Technology
Gorgoi
EMIL, BESSY II, Helmholtz-Zentrum Berlin
fur Materialien und Energie GmbHGray
Temple University

JuliusSatoruAtsushi
Dirk
KeisukeAtsushiAndrei
ShibeiHållstedt
Hamamoto
Hariki
Hauschild
Higashi
Higashiya
Hloskovsky
Huang

Excillum
RIKEN SPring-8 Center
Osaka Metropolitan University
Karlsruhe Institute of Technology (KIT)Osaka Prefecture University
Setsunan University
Photon Science, DESY
Okayama University

YoshioEiji
Shin
AustinTetsuyaEri
Kenichi

Ichii
Ikenaga
Imada
Irish
Ishikawa
Ito
Izumi

JTEC Corporation
Nagoya University
Ritsumeikan University
Lund University
RIKEN SPring-8 Center
Nagoya Institute of Technology
Yokkaichi research center, JSR Corporation

Fredrik

Johansson

KTH - Royal Institute of Technology /Sorbonne Université

Juhan Matthias
CurranJun
Takumi

Kahk
Kalha
Kano
Kawaguchi

University of Tartu
University College London (UCL)
Okayama University
Nagoya University

First Name

Last Name

Affiliation

Seiji
Victor
Yurii
Ivan
KentaroPardeep

Kawasaki
Kimberg
KotsarKruhlov
Kuga
Kumar

Murata Manufacturing Co., Ltd.
KTH, Royal Insitute of Technology
RIKEN SPring-8 Center
RIKEN SPring-8 Center
Toyota Technological InstituteDiamond Light Source

Deler
Tien-Lin
AndreasTianhui
Patrick

Langenberg
Lee
Lindblad
Liu
LömkerSPECS Surface Nano Analysis GmbH
Diamond Light Source
Uppsala University
Inst. Advanced Science Facilities, China
Stockholm University

Masatake
Natalia
Eugenie
MitsuseYasukoKojiroJan
Tetsuya
Hidetoshi
Martina
B. SimonMachidaMartinMartinez
MatsukiMatsumoto
MimuraMinar
MiyazakiMiyazakiMüllerMun

Scienta Omicron
Uppsala University
CEA-Leti, Université Grenoble Alpes
MB Scientific AB
RIKEN SPring-8 Center
Osaka Metropolitan University
University of West Bohemia
Ritsumeikan University
Nagoya Institute of Technology
University of Konstanz
Gwangju Institute of Science and Technology

Akihiko
Yuina
Andrew
SlavomirTappei
TakumiNakaguchi
NakataNaylorNemsakNishihara
Nishikubo

TakumaGoro

Nishioka
Nozue

Scienta Omicron
Ritsumeikan University
Uppsala University
Advanced Light Source
Meiji University
Kanagawa Institute of Industrial Science andTechnology
Osaka University
Osaka University

Satoshi

Ogawa

Takuo

OhkochiAndrii
Akane
Masaki

Orlov
Ose
Oura

Dep. Of Energy Engineering, Nagoya
University
Japan Synchrotron Radiation ResearchInstitute
RIKEN SPring-8 Center
Osaka University
RIKEN SPring-8 Center

Minna
MartenJay
Bui Van
Dibya
Piero

PatanenPatt
PaudelPho
PhuyalPianetta

University of Oulu
FOCUS GmbH
Temple University
JTEC Corporation
KTH - Royal Institute of Technology
SLACFirst Name

Last Name

Affiliation

Anna
Håkan
Jean-Pascal

Regoutz
RensmoRueff

University College London (UCL)
Uppsala University
Synchrotron SOLEIL

Christoph
Gerd
Akira
Yuuki
TomokiEric

Schlueter
Schönhense
Sekiyama
ShimadaShinozuka
Shirley

Deutsches Elektronen-Synchrotron DESY
Johannes Gutenberg University
Osaka University
Ritsumeikan University
Osaka Metropolitan University
National Institute of Standards andTechnology (NIST)

Marc
MichaelHisashiStephenVladimir N.
Satoru

Simon
Sing
Soma
Southworth
Strocov
SuzukiCNRS & Sorbonne University
Julius-Maximiliians-Universität Würzburg
Osaka Prefecture University
Argonne National Laboratory
Swiss Light Source, Paul Scherrer Institute
LASTI, University of Hyogo

Yukihiro
Munetaka
Yasumasa

Taguchi
TaguchiTakagi

Akio
Mona
Daisuke

TakanoTakaseTakegami

Masatoshi

Toda

HitoshiTomizuka

Osaka Metropolitan University
Toshiba Nanoanalysis Corporation
Japan Synchrotron Radiation ResearchInstitute
TOYAMA Co., LTD.
MB Scientific AB
Max Planck Institute for Chemical Physics ofSolidsJSR-U Tokyo Collaboration Hub, CURIE,JSR Corporation
TOYAMA Co., LTD.

Shigenori

Ueda

National Institute for Materials Science

Trung PhucVo

University of West Bohemia

LotharRegan

Weinhardt
Wilks

Karlsruhe Institute of Technology (KIT)
Helmholtz Zentrum Berlin für Materialien und
Energie GmbH

Dai
SusumuAtsushi
Yoshiyuki
Akira

Yamaguchi
Yamamoto
Yamasaki
Yamashita
Yasui

SatoshiYasunoMasatoYoshimuraTokyo Instruments, Inc.
Tohoku University
Konan University
National Institute for Materials Science
Japan Synchrotron Radiation ResearchInstituteJapan Synchrotron Radiation ResearchInstituteSPring-8 Taiwan Beamline Office

KelvinZhang

Xiammen University