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

SR X-RAYS

Advanced observation & manufacturing techniques

Energy tunability

Resonance
Anomalous effect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:
f0

2π
W=
h

H１

∞ f H2 n n H2 if H1 i + ∑Ei − Enn =1H２2

f1 + if2( )×ρ ε f ,Ei = hω + Ea

Energy selectivity

Use of anomalous dispersion

f(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

Marriage between XRD and XAFSXAFS & DAFS

f=f0+f’+if”

XAFSf”ｆ“ｆ‘

II~ (f0+f’+if”)2

DAFSenergy

Life time of catalytic activity

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

9085km0100

Duration of aging in engine exhaust (h)Self-regeneration of Catalyst
oxidation

reduction
Pd metallic
particleAB; A-site (La)
; B-site (Fe, Co); B-site (Pd)
; Oxygen

OY. Nishihata, J. Mizuki, et al.,Nature 418 (’02) 164

DXAFS (Energy Dispersive XAFS)Standard XAFS(Side-View)

SampleDouble crystal
monochromatorWhite x-rayθData acquisition timeI0IIonchamberIonchamber

3 - 30 min

DXAFS(Top-View)
Low energy

White x-ray →Sample
High energy

Bend crystal
Si(422)

Position sensitive
Detector (CCD)

1 - 100msec

Dispersive XAFS (DXAFS) for studying dynamic

White X-rays

poly-crometer

sampleCCDt

E

reductionoxidation
2.0
1.8
1.6

Detector

1.4μt

1.2

BL-14B1
Pd-K edge

1 ms

1.0

100 ms0.80.6

White XraysSample

0.4
0.2
0.0
24.3

24.4

24.5

24.6

24.7

24.8

Energy(keV)

24.9

25

25.1

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

Surface diffractometer + MBE
ーstudy of reaction frontー

Marriage between crystal growthand SR X-rays.

substrate

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 /frameqr

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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

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 dynamicalproperties 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 excitation

100meV

Strongly
Correlated
systems

Crystal field tran.
phonon10meV
1020
Q(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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

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 mirroranalyzer
sampledetector

Mechanism of High TC superconductor ?

Symmetry of doping-phase diagram
T （Ｋ）
400

T0300

TNTN

Anomalous
Metal phase200
Antiferromagnetic phase

TG
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”

CuUt”

Ut

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

X=0.154Calculated by K. Tsutsui

1.000Energy (eV)30210(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

toward future
Required energy resolution● Inter-band excitation: “U”~2eV
Excitations across the Mott / charge-transfer gap● Intra-band excitation: “t”~0.4eV
Excitations within bands across the Fermi level∆E~0.5eV∆E~0.1eV● Low-energy excitation: “J”~0.1eV
Excitations related to the spin degree of freedom∆E~0.05eV

Importance of the collaboration between
Experiment and theory

ElasticInelastic

Resonant

Actinide compounds

Non-resonant

Transition metalcompounds

Dynamical structure factor of IXS in the phonon energy region

ε(Q,ω)=εel(Q, ω)+εion(Q, ω)-1
χ(Q, ω)= -(Q2/4π2N) 1/ε(Q, ω)I(Q, ω)= F(εel)+G(εel)·H(εion)
I(Q,E)=E+

What does the phonon play a role on
superconducting?

Incident E(keV)

Resolution(meV)Spot size(μm2)

21.747

1.6

60 x 80

15.8166.0

120 x 90

T. Fukuda, J. Mizuki,
et al., P. R. B. in press

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

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

Speckle pattern
Intensity fluctuation by time
Coherent X-raysdomain

Self-correlation

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

XFEL

better spatial
coherence
better timeresolution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 = ∆X・∆Y・∆t

Bose degeneracy: δ= n・VC/V～0.1 for SPring-8
for XFEL(SASE-mode): δ～1010 !!

non-linear optical phenomena

SRUse of coherence, Bose degeneracy,
under multi-extreme condition

breakthrough?