Surface/Interface in scales

Photoemission (2)Surface ScienceSpaceThe Earth/Vacuum interface

Climates
Sea/Air interface

Iwao Matsuda
LASOR,Synchrotron Radiation Laboratory,
the Institute for Solid State Physics,
the University of Tokyo, JAPAN

Skins
Face/Air interface

http://imatsuda.issp.u-tokyo.ac.jp/index.htm

Surface/Interface in scalesGoods(solid/air interface)
Cooking(Oil/water interface)

Biomaterials surviving
in various environments

Molecules and atoms
in various conditions

Surface/Interface in scales
Things go on in a non-uniform system in any scale.
And there’re always interfaces (surfaces) that play their roles.
- Solid/Liquid- Solid/Gas- Liquid/Gas- Solid/Solid- Solid/Vacuum- ……..

My playground

Surface Analyses
Vacuum/Solid interface, solid surface

Given examples…….
AtomQuantum film

Monolayer

Atomic wire
Nanowire

Quantum dot

Nanometer-scale and atomic-scale structures on a solid surface.
Chemistry

Applied Physics

Physics
䞉Low-dimensional physics
䞉Quantum dynamics
䞉New physics

䞉Catalysis reaction䞉Ecology䞉Solutions for energy-shortage problem

䞉Bottom-up nanotechnology
䞉Atom technology
䞉New technological developments

Advantage of surface science:• Visualization of atomic configuration and electron density (LDOS) distribution in atomic scale• Direct determination of electronic structure (band, Fermi surface, etc…)

Surface Analyses

PhotonParticle

Particle-in / Particle-out
He scattering
Low-energy electron Diffraction (LEED)Transmission Electron Diffraction (TED)
Refection High-Energy Electron Diffraction (RHEED)
Refection High-Energy Positron Diffraction (RHEPD)
Photon-in / Photon-out
Grazing-angle incident X-ray Diffraction (GIXRD)Electron mean free pathsurface-sensitive ~ bulk sensitive
Electron mean free path (nm)ElectronPhotonBands(occupied)

An atomic layer

Core-levels

PES, UPS

CLS, XPSXASAES

Particle
PhotonNanoprobes
Scanning Tunneling Microscope (STM)
Atomic Force Microscope (AFM)

Spectroscopy with VUV~SX

Photon-in / Particle-out
Photoemission Spectroscopy (PES), Ultraviolet Photoelectron Spectroscopy (UPS)Core-level Spectroscopy (CLS), X-ray Photoelectron Spectroscopy (XPS)
X-ray Absorption Spectroscopy (XAS)
Auger Electron Spectroscopy (AES)
Bands(unoccupied)

Nanoprobes

Varieties of Surface analysis techniquesElectron Energy, Kinetic Energy (eV)

Probing electronic states
Probing electronic states/GVCN

Photoelectron spectroscopy

5GOKEQPFWEVQT

Vacuum level
9QTMHWPEVKQPBands(unoccupied)Electron$CPFICR(GTOKNGXGNPhotonBands(occupied)Core-levels

PES, UPS

CLS, XPS

Probing electronic states
CLS, XPS
ESCA (Electron Spectroscopy for Chemical Analysis)

What can be probed by photoemission
Vacuum level

Chemical shifts
Fermi level

Band Dispersions of- partially occupied states (metal)- fully occupied states (semiconductor)

Energy shift of core-levels- Different elements- Different chemical sites (environments)

Spectroscopy with VUV~SXEnergy range to probe- atomic structure- electronic structure- spin structureṼ ᵢᶇᶄᶄᶐᵿᶁᶒᶇᶍᶌṼ ᵟᶀᶑᶍᶐᶎᶒᶇᶍᶌᴾᵆᵣᵶᵟᵤᵱᵊᵬᵣᵶᵟᵤᵱᵊᵫᵡᵢᵇ
Ṽ ᵮᶆᶍᶒᶍᶃᶋᶇᶑᶑᶇᶍᶌᴾᵆᵟᵰᵮᵣᵱᵊᴾᵡᵪᵱᵊᴾᵱᶎᶇᶌᵋᶐᶃᶑᶍᶊᶔᶃᶂᴾᵮᵣᵱᵊᴾᵮᵣᵢᵇᴾ
Ṽ ᵶᵋᶐᵿᶗᴾᶃᶋᶇᶑᶑᶇᶍᶌ

Semiconductor surface
Atomic structure

Ṻ surface sensitive ~ bulk sensitiveṺ specification of all elements
Ṻ structure determination with high accuracy
Ṻ spin magnetic moment, orbital magnetic momentṺ direct determination of spin-resolved electronic structure

Scanning Probe Microscope

Cutting (expectation)

Scanning Tunneling Microscope (STM)

Silicon䠄䠄Si)
Diamond structure

Rohrer and Binnig (1982)

Dangling-bonds

STM

Scanning Tunneling Microscope

An experimental chamber- the Ultra High Vacuum condition- Isolation of vibration- Sample surface preparation

An STM image
Ideal surface

Scanning Tunneling Microscope
Real surface (STM image)It’s just an image of atomic scale protrusions
measured through tunneling currents.
What are them?
Tunneling currents between unoccupied statesand occupied states near Fermi level (EF).

Protrusions in STM could be surface atoms
G. Binnig, H. Rohrer et al., Phys. Rev. Lett. 50 (1983) 120.

The 7a1x1 (a1x1:3.8ύ) periodicity:
The Si(111)7x7 surface

Core-levels

Atomic Structure
Dimaer-Aadatom-Stacking Fault (DAS) model

K. Takayanagi et al.,Surf. Sci. 164, 367 (1985).

Surface components

F

C1: Atom binding to the adatom
C2: Rest atom
C3: Adatom
C4: Dimer atom
C5: Surface impurity atom
DAS model

Si(111)7x7Adatom
RestatomR. I. G. Uhrberg et al.,Phys. Rev. B 58, R1730 (1998).

Electronic states of Si(111)7x7
Bonding statesadatom
restatomSemiconductor surfaceBulk Conduction BandDAS model

Dangling-bond states

Electronic structure

Bulk Valence BandAdatom# of dangling bondsin the 7x7 unit cellᵿᶂᵿᶒᶍᶋᵘᴾᾀᾀᾁᶐᶃᶑᶒᵿᶒᶍᶋᵘᴾᾈᶁᶍᶐᶌᶃᶐᵋᶆᶍᶊᶃᵘᴾᵏᵏCornerholeRestatom

Band mapping

ARPES measurement

Angle-resolved photoemission spectroscopy(ARPES)

Si(111)7x7
Conventional measurements
Energy spectra at various angles
along symmetric crystal axis

M

[101]

*K

Band dispersion䠄E,k//䠅
1x1 SBZ
P. Martensson et al.,Phys. Rev. B 36, 5974 (1987).

Dangling bonds

Scanning Tunneling Spectroscopy
STM

DAS model

G. Nicolay et al., Phys. Rev. B 62 1631 (2000).

Scanning Tunneling Spectroscopy (STS), dI/dV

Rest atom state(Fully occupied)X

HV-Amplifier

Y

HV-Amplifier

XY-RampXY
HV-Amplifier

Display
AdatomRestatomSignal (dI/dV)

Adatom state(Partially occupied)

dIdV

Y

dI/dV
1.0
Sample Voltage (V)Z-ControlV’(I’)I’

U’- Charge transfer- Metallic surface

Reference㹼

Function Generator
R. Losio et al.,Phys. Rev. B 61, 10845 (2000).

B

Z

Feedback
Electronics

Lock-inAmplifier

C
dI/dV

X

X,Y,Z
Piezo
Tubetipsample

R. M. Feenstra et al.,Phys. Rev. B 66, 165204 (2002)

A

Bias Modulation: V’ = V + H sinZt
Current Modulation: I(V + H sinZt) = I(V) + dI H sinZtdV
Detection by phase matchingdIdV

҃ LDOS (Local Density Of States)

C. Bai, Scanning Tunneling Microscopy and its Application(Springer,1992)

Scanning Tunneling Spectroscopy
Tunneling
DAS
model Spectroscopy at different sire

Differential Current Imaging Tunneling Spectroscopy

Adatom state @ - 0.35 V

Si(111)7x7

Electron Diffraction
Reflection High-Energy Electron Diffraction (RHEED)(Electron) Wave diffracts at a periodic structure.

15 keV
Rest atom state @ - 0.8 V
AdatomRestatom

UPSIPS
Back bond state @ - 1.7 V
R. J. Hamers et al.,Phys. Rev. Lett. 56, 1972 (1986).

Reflection High-Energy Electron Diffraction
RHEED pattern of Si(111)7x7 at 15 keVSi(111)7x7

Variations of ordered surface phasesSi(111)7x7+ 1 ML Ag

Si(111)3x3-Ag+ 0.4 ML Au

Si(111)5x2-Au
S. Hasegawa et al.,Prog. Surf. Sci. 60, 89 (1999).

Numerous numbers of ordered phases- Adsorbates (atom, molecule)- Coverage- Co-deposition- Substrate- Deposition temperature- Deposition rate
> 300 reported- Deposition steps
for Si substrate- ….

Si(111)3x3-Ag


STM imageSi(111)3x3-Ag


STM simulation

SiAg
Ag

Si
Tunneling current distribution

Structure model

STM protrusions do not match the atom positions.
S. Watanabe et al., Phys. Rev. B 44, 8330 (1991).

Si(111)3x3-Ag


Atomic Structure and CLS spectraSi(111)3x3-Ag


Atomic Structure and CLS spectra

S1
S2R.I.G Uhrberg et al., Phys. Rev. B 65, 081305(R) (2002).

Si(111)3x3-Ag

Si(111)3x3-Ag
Electronic Structure- Metallic surface-state bandin the bulk band gap

Binding Energy (eV)Fermi level
䠄EF䠅Electronic Structure
Angle-Distribution Curves (ADC)

Energy-Distribution Curves (EDC)

Fermi surfacek// (ύ-1)

Scanning Tunneling Spectroscopy

Si(111)3x3-Ag

STM



Electronic Structure

2D-fitG. Nicolay et al., Phys. Rev. B 62 1631 (2000).

Scanning Tunneling Spectroscopy (STS), dI/dV

X

HV-Amplifier

Y

HV-Amplifier

XY-RampXY
HV-Amplifier

Display

Signal (dI/dV)

dIdV

Y

dI/dV1.0
Sample Voltage (V)Z-ControlV’(I’)

I’U’

Reference

B

Z

Feedback
Electronics

Lock-in
AmplifierCdI/dVX

㹼Function Generator

X,Y,Z
Piezo
Tubetipsample

R. M. Feenstra et al.,Phys. Rev. B 66, 165204 (2002)

A

Bias Modulation: V’ = V + H sinZt
Current Modulation: I(V + H sinZt) = I(V) + dI H sinZtdV
Detection by phase matchingdIdV҃ LDOS (Local Density Of States)

C. Bai, Scanning Tunneling Microscopy and its Application(Springer,1992)

Si(111)3x3-Ag

Si(111)3x3-AgElectron Standing wave
at monatomic stepElectron Standing wave

STM
(Vt: -0.7 V)

dI/dV(Vt: -0.9 V)

dI/dV(Vt: -0.7 V)

I. Matsuda et al.,Phys. Rev. Lett. 93, 236801 (2004).

Si(111)3x3-Ag


The 2-D Free electron metallic band

Metal surface
Electronic structureAg(111)Cu(111)

LⅬ
Ⅼ gap
Surface state in L point gap

F. Reinert et al., Phys. Rev. B 63, 115415 (2001).
G. Nicolay et al., Phys. Rev. B 65, 033407 (2001).

F. Reinert et al.,Phys. Rev. B 63, 115415 (2001).

Au(111)

Surface Rashba effect
E. I. Rashba, Sov. Phys. Solid State 2, 1109(1960)

Kramers degeneracy : E(k,)=E(k,)Time reversal symmetry: E(k,)=E(-k,)Space inversion symmetry: E(k,)=E(-k,)Breakdown at a surface
Appearance of the two surface-state bands

Spin-split bands

Spin-Orbit Coupling
Hamiltonian

H SOC

Pauli matrix&&& &!
V  (V u p)(v s  L )
2 2
4me c
Electric field(0,0,Ez)

J. Henk et al., Phys. Rev. B 68, 165416 (2003)

Fermi surface mapping with spin-resolved photoemission spectroscopy

Au(111)

H. Moritz et al., J. Elec. Spec. Rel. Phenom. 124, 263 (2002).

Spin-orbit splitting

kx,ky,kz,Vx,Vy,Vz are determined with synchrotron radiation
COmplete PHotoEmission Experiment (COPHEE)

Spin-slit surface-state band
Mott detector

Spin-resolved photoemission spectroscopy

J. Henk et al., Phys. Rev. B 68, 165416 (2003)

Au(111)

M. Hoesch et al., Phys. Rev. B 69, 241401(R) (2004)

Surface Rashba effectQuantum Size effect, Quantum Confinement EffectA problem of particles (electrons) in a boxEnergetically quantized electronic states
Quantum Well States (QWS)
Free electron model

Metal films

Fermi ring(cylinder)

Fermi sphereElectronic structure

boundary condition
I + 2 kz d + I S nHypersurface

discrete
momentum space

3-D Crystal
fcc

Surface BZ

Quantum Confinement Effect
Quantization of a bulk band

3-DBrillouin
Zone

Uktrathin Ag(111) film (quantum film)

n=1

Fermi surface of Ag(111) slab calculation

n=2(15 ML-Ag(111) free-standing slab)

n=3

QWS

Ag crystalFermi
surface6-foldsymmetryboundary condition
I + 2 kzenv d + I S n
Summation of the wave functionsof + kz and -kz

weight:spectral intensity

Our interests

Epitaxial 15ML-Ag(111) film on Si(111)

Quantum Size effect, Quantum Confinement EffectThickness : Semiconductor
de Broglie wave, ~ 100 nm
Metal
Fermi wavelength, ~ 1nm

Kinetic Energyky(ύ-1)

Large ratio of a surface (interface) monatomic layer to film atomic layers: > 1 / 10

Ultrathin film (2-D growth)

QWS
Surface topmost layer
metalInterface monatomic layerkx (ύ-1)

Semiconductor Surface ScienceIn addition to band features expected,new features, kinks, hexagons at *are observed.

Choice in Semiconductor Surface ScienceA periodic array of atomic wires:
STM image

Photoemission Fermi surface

semiconductor
Engineering Fermi surface topology
Electronic topological transition
by an interface monatomic layer

Experiments
Exchange of interface layer between film and substrate
Substrate: vicinal Si(111) (1.8㼻㼻-off)

Si(111)4x1-In

Ag thin film
on 7x7Si(111)7x7

aint = 1.3 nm

kF ~ 0.5ύύ-12-DIn deposition(HT:~600K)

Ag deposition(LT:~120-150K)

Si(111)4x’2’-InSi(111)4x1In

Epitaxial
Ag thin film
on 7x71-D
Si(111)8x2-In

Anneal (RT)Ag thin film
on 4x1(4x’2’)-In

ARPES

Epitaxial
Ag thin film
on 4x1-In

Results & Discussions

Results & Discussions

BL3.2 VUV Elettra, Italy

T. Uchihashi et al., Phys. Rev. Lett. 96, 136104 (2006)

STM: Ag film / Si (111)4x1-In

hv=50eVroom temperature

Ag film (~1nm) / Si (111)7x7

1.0 ύ -1

Ag film (~1nm) / Si (111)4x1-In

1.0 ύ -1

Results & Discussions

BL3.2 VUV Elettra, Italy

ARPES: Ag film (~1nm) / Si (111)7x7

BL3.2 VUV Elettra, Italy

ARPES: Ag film (~1nm) / Si (111)4x1-In
Calculation

Photoemission Fermi surface

Results & Discussions(6 ML-Ag(111) free-standing slab)

hv=50eVroom temperature
Photoemission Fermi surface

weight:spectral intensity

Different kz(E) or E(kz)Surface electronic structures
Schroedinger electron

Solid Surface
Playgrounds for low-dimensional physics

Surface electronic structures
Spin-orbit interaction

Dirac-Wely electron

Quantum spin Hall phase(topological insulator)
Kane,Mele, PRL(2005), Bernevig, Zhang, PRL (2005)

Dirac equation:

Surface Rashba effect• bulk = gapped (insulator)• gapless edge states -- carry spin current, topologically protectedrobust against nonmagnetic impurities• spin analogue of the quantum Hall effect “new state of matter”• no field required

2D

Spin current(Kramers pairof gapless edge states)

3D

Quantum Spin Hall Phase

1D-edge states

2D-edge statessurface states

Topological band theory
Z2 topology in band structure
Parity: G iSurface electronic structures

r1GiN[2mWith inversion
symmetry*im 1Gi&wmn (k )Parity eigenvalue+1: symmetric-1: asymmetric

1/8ofthe3DBrillouinZone(BZ)

Edge-statesof topological insulators(ex. Bi0.9Sb0.1)

Surface statesof (semi)metal crystals
with strong spin-orbit interaction(ex. Bi, Au)- Schockley states- Tamm states-Odd number ofFermi level crossings-Rashba effect- spin-degenerate- spin-split- spin-split

Z2 invariants: zero

Z2 invariants: zero

Z2 invariants: nonzero

No inversion
symmetryuk ,m 4 uk ,nTime-reversal
operator
time-reversal invariant,satisfying *i=*i+G(001)

Typical surface states
within the bulk band gap(ex. Si, Ge)

det>w(*i )@Pf >w(*i )@Z2 topological numbers: products of the parity eigenvalues

expressed as the productover all eight points(001) 2D-BZ
with Fermi arcs of surface states enclosing the specific / points

given by products of four Gḙs forwhich *i reside in the same plane

If the two k-points have opposite signs, the Fermi surface crosses between the two points.

+++++++++++

time-reversal
invariant momenta, /Motivation

The Bi1-xSbx caseExperiment
Bi0.9Sb0.1

ARPES

Elaborateband structure?

Bi0.9Sb0.1

theory: Fu et al., Phys. Rev. Lett. (’07)
exp.: Hsieh et al., Nature (’08)

ARPES

Theory0(111) 2D-BZ

theory: Fu et al., Phys. Rev. Lett. (’07)
exp.: Hsieh et al., Nature (’08)+*

Odd number (five) of Fermi points
between * and M.
Agreement

Existence of Fermi crossingof a spin-nondegenerate band
between * and M.

Spin-polarizedband structure?

Spin- and angle(momentum)-resolved photoemission spectroscopy

How do we determine momentum of electrons?
Electron spectrometers from VG, Scienta, Omicron, Specs….
How do we determine their spin coordinates?
Spin detector , Spin polarimeterSpin-detector (Mott detector)

Spin-detector (Mott detector)

25 kV-Compact Mott detector

Spin-resolved band mapping of Bi crystal filmwith a 25 kV-Compact Mott detector

by A. Kakizaki et al.

- 25 keV electrons- spin-orbit interaction- Au target

Rashba effectof the surface state

T.Hirahara et al., Phys. Rev. B 76,153305 (2007).

Spin-detector (Mott detector)
Spin-resolved band mapping of Bi1-xSbx crystal
with a Compact Mott detector
COmplete PHotoEmission Experiment (COPHEE)

Spin-detector (VLEED detector)
Very Low- Energy Electron Diffraction (VLEED) detector
Bi0.9Sb0.1

by T. Okuda et al.
T. Okuda, Y. Takeichi, Yuuki Maeda, A. Harasawa,
I. Matsuda, T. Kinoshita, and A. Kakizaki,
Rev. Sci. Instrum. 79, 123117 (2008).
Fe(001)

Low
spin efficiency'E=100~200meVO/Fe(001)

Mott detector

H. Moritz et al.,J. Elec. Spec. Rel. Phenom. 124, 263 (2002).

Hsieh et al.,Science 323, 919 (2009).

- 6 eV electrons- exchange interaction- Fe, O/Fe target

Spin-detector (VLEED detector)

Motivation

SPECS-PHOIBOS150+VLEED detector

Bi0.9Sb0.1

Odd number (five) of Fermi points between * and M.
Spin-polarized band structure?
ARPES
theory: Fu et al., Phys. Rev. Lett. (’07)
exp.: Hsieh et al., Nature (’08)

High-efficient spin detection (100 times better than the Mott detector)
A combination with high-resolution analyzer

high-resolution spin-resolved
photoemission spectroscopy

'E< 30 meVResults and Discussion

Results and Discussion

high-resolution spin-resolved photoemission spectroscopy

Bi1-xSbx

Measurement condition
x=0.12He ID(21.2 eV)

'E =50 meV, 'T=ᶠ1ᶟ
T~130 K
Seff = 0.32 ᶠ 0.04,
determined by the polarizationof secondary electrons from Fe(001).

x=0.12,0.13

Results and DiscussionṺThe second generation samples

H.Zhang et al., Nature Phys. 5 438 (2009).

Bi2Se3Spin-resolved band plots
on spin-integrated grayscale band diagram

Edge-statesof topological insulators(ex. Bi~0.9Sb~0.1)-Odd number of
Fermi level crossings

Bi2Te3Well-defined stoichiometry
Single-band (One Kramers pair)
Wide bulk band gap (300 meV, 3600 K)- spin-split- Z2 invariants: nonzero
Y. Xia et al., Nature Phys. 5 398 (2009).

D. Hsieh et al., Nature 460 1101 (2009).

Summary
Surface Science is everywhere. Global to Atomic scale.
For solid/vacuum interface (solid surface), we have advantages of• Visualization of atomic configuration and electron density (LDOS) distribution in atomic scale• Direct determination of electronic structure (band, Fermi surface, spin, etc…)

Solid surfaces are important playgrounds for studying lowdimensional physics.
Photoemission spectroscopies with synchrotron radiation are theimportant experimental tools.

Frontier Spectroscopy experiments
at SPring-8 BL07LSU:
with time-resolution and at nano-spaceSPring-8 BL07LSU

SPring-8 BL07LSU
Specification
High-brilliant soft x-ray
hv: 250 eV ῍2 000 eVFour spectroscopy end-stations

resolution: E/'E: >10,000
Beam sizeᾉ x < 10 m(x < 90 nm with ZP)(x < 400 nm with K-B mirror)
Fluxᾉᾍ1012 photons/sTime-resolved angle-resolved photoemission spectroscopy
with a 2D-ARTOF spectrometer and fs-pulse lasersᵲᶇᶋᶃᵋᵰᶃᶑᶍᶊᶔᶃᶂᴾᶑᶍᶄᶒᴾᵶᵋᶐᵿᶗᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗᴾᶑᶒᵿᶒᶇᶍᶌᵲᵰᵋᵱᵶᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗᵑᵢᵋᶑᶁᵿᶌᶌᶇᶌᶅᴾᶎᶆᶍᶒᶍᶃᶊᶃᶁᶒᶐᶍᶌᴾᶋᶇᶁᶐᶍᶑᶁᶍᶎᶃᴾ
ᵑᵢᴾᶌᵿᶌᶍᵋᵣᵱᵡᵟ

Spatial resolution: 50 nmᲢx,yᲣ
Depth profileᲴ 0.1 nmᲢzᲣ

Polarizationᾉ linear, circular

SR pulse-width: ~ 40 psᵳᶊᶒᶐᵿᴾᶆᶇᶅᶆᵋᶐᶃᶑᶍᶊᶓᶒᶇᶍᶌᴾᶑᶍᶄᶒᴾᵶᵋᶐᵿᶗᴾᶃᶋᶇᶑᶑᶇᶍᶌᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗ
ᵦᵭᵰᵬᵣᵲ

Monochromator:
Slit-less variable included angle VLS-PGM

Ultimate resolution
Measurement of solid, liquid, gas
Free-Port station
Open for experimental system of usersᵲᶇᶋᶃᵋᵰᶃᶑᶍᶊᶔᶃᶂᴾᶑᶍᶄᶒᴾᵶᵋᶐᵿᶗᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗᴾᶑᶒᵿᶒᶇᶍᶌ

ᵲᶇᶋᶃᵋᵰᶃᶑᶍᶊᶔᶃᶂᴾᶑᶍᶄᶒᴾᵶᵋᶐᵿᶗᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗᴾᶑᶒᵿᶒᶇᶍᶌ

ᵲᵰᵋᵱᵶᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗ

ᵲᵰᵋᵱᵶᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗ
The measurement system
Manipulator

ARTOF

VG CLAM2Laser systemWavelength : 200-800 nm
Pulse: < 50fs,
Power: nJ/pulse (1kHz - 80 MHz)
2.5 mJ/pulse (1-2 KHz)

ᵲᶇᶋᶃᵋᵰᶃᶑᶍᶊᶔᶃᶂᴾᶑᶍᶄᶒᴾᵶᵋᶐᵿᶗᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗᴾᶑᶒᵿᶒᶇᶍᶌ

ᵲᵰᵋᵱᵶᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗT⁪‒⅚ T⁫ ⁤⁓⁠⁙⁗ ”‡‟ ‣․†‧⁳≋ T⁪‒⅚ T⁫⅚ ‿⁓⁪†‒⁤⁓⁠⁙⁗ ‒”‡‟ ‣‧⁳≌‷⁠⁗⁤⁙⁫‒⁤⁓⁠⁙⁗≠‣ †‧⁗⁈ᵲᶇᶋᶃᵋᵰᶃᶑᶍᶊᶔᶃᶂᴾᶑᶍᶄᶒᴾᵶᵋᶐᵿᶗᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗᴾᶑᶒᵿᶒᶇᶍᶌ

ᵲᵰᵋᵱᵶᴾᶑᶎᶃᶁᶒᶐᶍᶑᶁᶍᶎᶗ

Ṻ ᵐᵋᵢᴾᵿᶌᶅᶊᶃᵋᶐᶃᶑᶍᶊᶔᶃᶂᴾᶋᵿᶎᶎᶇᶌᶅᴾᶕᶇᶒᶆᶍᶓᶒ ᶒᶆᶃᴾᶑᵿᶋᶎᶊᶃᴾᶐᶍᶒᵿᶒᶇᶍᶌ
Pump(laser)-Probe(synchrotron radiation) time-resolved photoemission experimentson relaxation after the surface photovoltage effect of Si(111)7x7Si(111)ᾉbulk valence band, hv=250 eVT⁫

E-scanT⁪ᵑᵢᵋᶑᶁᵿᶌᶌᶇᶌᶅᴾᶎᶆᶍᶒᶍᶃᶊᶃᶁᶒᶐᶍᶌᴾᶋᶇᶁᶐᶍᶑᶁᶍᶎᶃᴾ

ᵑᵢᵋᶑᶁᵿᶌᶌᶇᶌᶅᴾᶎᶆᶍᶒᶍᶃᶊᶃᶁᶒᶐᶍᶌᴾᶋᶇᶁᶐᶍᶑᶁᶍᶎᶃᴾ
ᵑᵢᴾᶌᵿᶌᶍᵋᵣᵱᵡᵟPOElement and chemical analysis
in nano-regionᵑᵢᵋᶑᶁᵿᶌᶌᶇᶌᶅᴾᶎᶆᶍᶒᶍᶃᶊᶃᶁᶒᶐᶍᶌᴾᶋᶇᶁᶐᶍᶑᶁᶍᶎᶃᴾᵑᵢᴾᶌᵿᶌᶍᵋᵣᵱᵡᵟ

Thank you for your kind attentions.

ᵑᵢᵋᶑᶁᵿᶌᶌᶇᶌᶅᴾᶎᶆᶍᶒᶍᶃᶊᶃᶁᶒᶐᶍᶌᴾᶋᶇᶁᶐᶍᶑᶁᶍᶎᶃᴾᵑᵢᴾᶌᵿᶌᶍᵋᵣᵱᵡᵟ