New Scientific Possibilities&Directions

Jun’ichiro Mizuki
Quantum Beam Science Directorate
Japan Atomic Energy Agency (JAEA)

Key words:-In situ- Dynamics

Why SR?
Realization of abundant, secure, sustainable society
Growth of industry

Natural environment

Persistent energy

Sophisticated infor.
& comm. tech.

Quantum dot,
optoelectronics

Socila welfare
Sophisticated medicine

Tech. of Solar, hydrogenenergy use

Hydrogen storage
materials

catalyst

Spintronics materials

Manufacturing tech. ofmaterials
Biomedicine

Nano-tube

molecular・
Bio-materials

glass

Advanced observation & manufacturing techniquesWhy SR?
Realization of abundant, secure, sustainable society
Growth of industry

Natural environment

Persistent energy

Sophisticated infor.
& comm. tech.

Quantum dot,
optoelectronics

Socila welfare
Sophisticated medicine

Tech. of Solar, hydrogenenergy use

Hydrogen storage
materials

catalyst

Spintronics materials

Manufacturing tech. ofmaterials
Biomedicine

Nano-tube

molecular・
Bio-materials

glass

SR X-RAYS

Advanced observation & manufacturing techniquesWe would like to live in pollution-free environment

Three-way catalyst
HC, N2, O2

Pd,Pt,Rh

HCCONOX

H2O+C
CO2
N2+O2oxidationreduction

CO-NOX crossover point

conversion（％）

1008060HC(oxidation)CO(oxidation)

NOx(reduction)

40
operatingwindow

20

Theoretical point

013.5

1414.51515.5Air-to-Fuel ratio

Feedback-controlled engine management causes
Reductive and Oxidative (Redox) Fluctuations
At 1~4Hz within ±4%16Life time of catalytic activity

conversion %100Intelligent Catalyst(La(FeCo)O3) + Pd0.05
95
excess Pd

9085km0100

Duration of aging in engine exhaust (h)Energy tunability

Resonance
Anomalous effectEnergy selectivity

Use of anomalous dispersionf(Q,ω)=f0(Q)+f’(ω)+if”(ω)
K-K relation
From Elements of modern x-ray physics by J. Als-Nielsen and D. McMorrow

Quantum Mechanical Description
P2
H=2mFree particle:

Interaction with an electromagnetic
field:
r r2P − eA
P 2 e2 2 e r r
H==+A − P• A
2m2m 2mm()Transition probability W:
f02π
W=h

H１∞ f H2 n n H2 if H1 i + ∑Ei − Enn =1H２2f1 + if2( )×ρ ε f ,Ei = hω + Ea

Marriage between XRD and XAFSXAFS & DAFS

f=f0+f’+if”

XAFSf”ｆ“ｆ‘

I

I~ (f0+f’+if”)2

DAFSenergy

Anomalous Diffraction Intensity around Pd k-edge
Oxidized sample
F (100) ~ f A − f B − fO

Pd K-edge

EF (110) ~ f A + f B − fO

Anomalous Diffraction
at (110), (100) ofReduced sample.
No change is observed !

Pd atom is out of thePerovskite lattice!?

Self-regeneration of Catalyst
oxidation

reduction
Pd metallic
particle
AB; A-site (La)
; B-site (Fe, Co); B-site (Pd)
; OxygenOY. Nishihata, J. Mizuki, et al.,Nature 418 (’02) 164

But, one referee still has doubts
about the model because
the experiments were done ex-situ

Questions:●How fast does Pd move?
●What temperature does Pdstart moving?

In-situ experiment
Y. Nishihata et al., nature 418, (2002) 164

DXAFS (Energy Dispersive XAFS)Standard XAFS
Data acquisition time(Side-View)

SampleDouble crystal
monochromatorWhite x-ray
θ



I0

I

Ion
chamberIon
chamber3 - 30 min

DXAFS(Top-View)
Low energy

White x-ray →Sample
High energy

Bend crystal
Si(422)

Position sensitiveDetector (CCD)

1 - 100msec

(a)Normalized absorption

Normalized absorption

XANES(400℃)

1.00.8
0.6
0.4
0.2
020

15

Time (s)(b)
1.00.8
0.6
0.4
0.2
020

10

5024.30

24.34

24.38

24.42

Energy (keV)

Reduction

15Time (s)

1050

24.30

24.34

24.38

24.42

Energy (keV)

OxidationSelf-regeneration model
Atomic levelcomplex

Segregatedat 1-3nm

Restored toatomic level

Intelligent
Catalyst
Self-regeneration !

Perovskite
Precious
metal

Oxidative

Reductive

Oxidative

Conventional
catalyst

Dispersed onconventionalceramics

Enlargement of Further enlargement
precious metals and deterioration

Super-intelligent catalysts !

ABPtRhOPdBBAAOO

Live in a convenient & sophisticated Society- new information & communication tech -ρ(E)Semiconductor nano-structure

Bulk

ρ(E)

E

Quantum well

ρ(E)

E

Quantum dot<~50nmE

Semiconductor Laser

InAs / GaAs(001)p-AlGaAs crude layer
GaAs active layer
n-AlGaAs crude layer
n-GaAs substrate
InAs quantume dot（～20nm）
1.3～1.5 μm wavelengths

InAs/GaAs(001) self-assembledquantum dots
MBE・MOCVD（Stranski-Krastanow growth）
GaAs-InAs 7% mismatch(b) In 0.21 ML(a) template

wetting layerc(4x4)
GaAs(001)(c) In 2.1 MLislanding(d) GaAs 5nmcappingProblems to be overcome in QDs fabrication• high uniformity in QDs size & shape• control of chemical composition• high QDs density- Understanding the growth mechanism- Real time monitoring during the growthSurface diffractometer + MBE
ーstudy of reaction frontー

X 線回折計結晶成長装置Marriage between crystal growthand SR X-rays.

基板αsubstrate

Source of element（from home page of Kishimoto Lab., Sophia Univ.）

M. Takahasi J. M. et al., Jpn. J. Appl. Phys. 41 (’02) 6247

Experimental configuration
[110]
220

2θ

αf

X-ray CCD
220
planes[001]

8 s /frame

qr

2θ

[001]

sampleθ

X-rays αi=0.2°[110]

Interpretation of CCD images
4.9ML InAs
at 480℃

I (2θ , α f ) ∝ T (α i , z )T (α f , z ) S (2θ )S (2θ ) : kinematical θ−2θ spectrum

strain ( reciprocal space)
T (α i,f , z ) : multiple-diffraction effect2θ

height ( real space)αfWhat is T(α,z)?
Experiment

Intensity ( arb. units )ε=1.02

1.03
1.04
1.05
1.06
1.07

2θ

0

αf

12

α / αc3

What is T(α,z)?
Calculation

Experiment

Intensity ( arb. units )ε=1.02

1.03
1.04
1.05
1.06
1.07

2θ

0

αf

12

α / αc3

What is T(α,z)?
Calculation

Experiment

Intensity ( arb. units )ε=1.02

1.03
1.04
1.05
1.06
1.07

2θ

0

αf

12

α / αc3

Height of QDsz

Results(1)Stage 1: InAs growthtime

InAs
thickness

0s

0 ML

260 s

1.8 ML346 s

2.4 MLheightz

5.1 nmResults(2)Stage 2: Annealingtime

heightz

346 s

5.1 nm404 s

5.5 nmResults(3)Stage 3: GaAs encapsulation
timeGaAs
thickness

404 s

0 nm

452 s

0.4 nm827 s

3.6 nmAnnealing of 3ML InAs dotso(1) T=470 Co(2) T=446 C

Evolution of 3ML-InAs/GaAs(001) during
growth interruption
T=470oC

Evolution of 3ML-InAs/GaAs(001) during
growth interruption
T=470oC

T=446oC

Stacking at Td=478oC and Tc=450oC

PL (8.5K)
InAs
2.8ML
GaAs
30 nm

Discover new scientific phenomena
and invent new materials

Electrons in mean field
Quantum Hall effect

Heavy fermion

Strongly correlated electrons

Colossal magnetoresistanceHigh TC superconductor

Complex interplay between Charge, Spin, Orbital
degrees of freedom

Actor /actress in materials is the electron !

structure?

Function/property
conductivity
catalysis

Theory (electronic states)

magnetism
dielectrics

spectroscopy

How are electrons correlate
in materials ?

Potential acting on electrons

ele.
-eele.
-eele.

ele.

ele.

ele.

Material 1Material 2

electron

electroninteraction

ele.

ele.

interaction

ele.

ele.

Material 1

Material 2

Dynamics

Observation space

In what space should we measure physical properties?

Real time (t)Energy space (ε)

Real space (r)Momentum space (q)How do we know the potential for electrons?

Dynamics!
Observation of dynamical
properties of electrons and atoms(ωf, kf )(ωi, ki )Q = ki-kf
ΔE=ωi-ωｆ≡ω
inelastic scattering!

Elementary Excitations in Solids

100eV
10eV
1eV

Compton scatt.

PlasmonInterband electron transition
magnonStoner excitation100meVStrongly
Correlated
systems

Crystal field tran.
phonon10meV1020Q(A-1)

Inelastic Scattering[I (Q, E ) ~ [V (Q)] 1 − e2] • Im χ (Q, E )− βE −1

Interaction of probe

Generalized susceptibility

For neutrons

Spin susceptibility
Nuclear susceptibility

For X-rays
For electrons

Charge susceptibility

χ(Q,E )= -(Q2/4π2N) 1/ε(Q,E)
Dynamical dielectric function

Inelastic X-ray scattering
22⎞⎛peee1 ⎛⎞2⎟j⎜H =∑A(r j )⋅ p j +A(r j )−⎜ p j − A(r j )⎟ = ∑2⎟⎜c2mc⎠
j 2m ⎝j⎠⎝ 2m mc
2Fermi' s golden rule I ∝2πhf A2 i +f A ⋅p n L m A ⋅p i2(Ei − Em + hϖ − iΓ )• The first term: non-resonant inelastic scattering– All electrons （Ze） are contributed ⇒ phonon excitation• The second term: resonant inelastic scattering (RIXS)– Electrons on the specific atom are contributed.
– Resonance enhancement– Element specific ⇒ electronic excitation

Set-up of Inelastic Scattering Spectrometer at BL-11XU

Observed energy
Resolution
at 6.5 keV

Picture of the spectrometer
at BL-11 XU, SPring-8
Focusing mirror

analyzer
sampledetector

RIXS of 3d transition elements
Ｋ-edge （1s→4p、several keV）
(a) absorption(b) interaction between
1s core-hole and 3d electron(c) X-ray emissionf A ⋅ p n n V1s −3d m m A ⋅ p iI∝ ∑( E − En + hϖ f − iΓ)( Ei − Em + hϖ i − iΓ)m, n f2

Mechanism of High TC superconductor ?

Symmetry of doping-phase diagram
T （Ｋ）
400

T0300TNTN

Anomalous
Metal phase200
Antiferromagnetic phaseTG
100

Superconducting
phase
0.3

Tc
0.2

Electron concentration（per Cu atom）

Pseudo-gap
phaseSuper.

0.1

00.1

Tc
0.2

0.3

Hole concentration（per Cu atom）

Schematic diagram of electronic states
energyenergyOt, t”

Cu

Ut”

Ut

DOS
DOS(ii) Hole doped (iii) Electron doped
systemsystemElectron doping

X=0.154Calculated by K. Tsutsui

1.000

Energy (eV)

302

10
(π,π)

(π/2,π/2)(0,0)

Momentum Transfer q(π/2,0)(π,0)
Theory(small cluster)

RIXS spectra
Dynamical density response function

The electron involved in dynamical density response function
can be selected by RIXS !
K. Ishii, J. M. et al.,PRL. 94 (’05)207003

Future direction

Charge dynamics in strongly
Correlated electron systems-Excition across Mott/chargetransfer gapt”

U: ΔE~0.5eV-Excitation within bands acrossthe Fermi levelt: ΔE~0.1eV
Ut-Excitations related to theSpin degree of freedom
J: ΔE~0.05eV

Importance of the collaboration between
Experiment and theory

Elastic
Inelastic

Resonant

Actinide compounds

Non-resonant

Transition metalcompoundsWhat does phonon play a role on
superconducting?

Incident E(keV)

Resolution(meV)Spot size(μm2)

21.747

1.6

60 x 80

15.8166.0120 x 90

Anomalous dispersion of LO Cu-O bond stretching phonon modes
observed by Neutron inelastic scattering(Pintschovius et al., Physica B 174 (1991) 323)

La2-XSrXCuO4

0.04

0.07

0.29
0.12

T. Fukuda, J. Mizuki,
et al., P. R. B. in pressFuture plan
Study in Dynamics of Materials to investigate Physical
Properties, Chemical Reactions, Crystal Growth, etc.

Real time (t)Energy space (ε)

Real space (r)Momentum space (q)complementaryTest line of Linear motor car

Room temperature superconductor

Dynamics in time domain
Tracking the motion of charges in a terahertz
light field by femtosecond X-ray diffraction
A. Cavalleri et al., Nature 442 (‘06) 664

Time-dependent
Structure factor

Excitation of phonon polaritons in LiTaO3

Use of coherence for slow dynamics
Time dep. intensity

BL-22XU

Speckle pattern

Coherent X-raysdomain

X-ray Photon
Correlation
Spectroscopy

speckleUse of coherence for slow dynamics
Domain motion of relaxor by coherent X-ray diffraction: (t, Q)

BL-22XU(H K L)
speckleAuto-correlation function X-ray Photon

Correlation
Spectroscopy(H K L)+δIntensity fluctuation

K. Ohwada, et al., preparation

Future direction for SR performance:
more lower emittancemore shorter pulse duration

XFEL

better spatial
coherence
better timeresolution

Domain Dynamics by Coherent X-ray Diffraction
Time dep. intensity

Speckle pattern
Intensity fluctuation by time
Coherent X-raysdomainSelf-correlation

Domain fluctuation of Relaxor PZT-9%PT
91%Pb(Zn1/2Nb1/2)O3+9%PbTiO3

Speckle around (200)msec

Kuwata et al., Jpn. J. Appl. Phys. Vol. 21 (1982) 1298.
msec

K. Ohwada, private comm.

Coherence：Bose condensation
Photon number in a coherent volume
Longitudinal (temporal) coherence: σt ～2h/Δω
Transverse (spatial) coherence: σx,y ～λ・L/2πSX,YCoherent volume: VC =σX・σY・σt = λ2・L2・2h/(4π2・S2・Δω)Beam Volume:V = ΔX・ΔY・ΔtBose degeneracy: δ= n・VC/V～0.1 for SPring-8for XFEL(SASE-mode): δ～1010 !!

non-linear optical phenomena

DynamicsReal time (t)Energy space (ε)

Real space (r)Momentum space (q)from Observation of |E(t)|2 toward E(t)Phase information of electron
Manipulation of electron wavefuctionSR
Use of coherence, Bose degeneracy,
under multi-extreme condition

breakthrough?