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The studies of electronic structure of The studies of electronic structure of strongly correlated materials by the strongly correlated materials by the combination of HAXPES and other combination of HAXPES and other

techniquestechniques

Munetaka TAGUCHIMunetaka TAGUCHI((RIKEN/SPringRIKEN/SPring--8, Excited Order Research team8, Excited Order Research team))

HAXPES200920-22/May/2009

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ContentsContents

Introduction

NiO

Magnéli phaseTi4 O7

Summary

Introduction

NiO

Magnéli phaseTi4 O7

Summary

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La1-x Srx MnO3 V1.98 Cr0.02 O3 High Tc cuprates

Horiba et al., PRL 93 236401 (2004)

Taguchi et al., PRB 71 155102 (2005)

Kamakura et al.,EPL 68 557 (2004)

Taguchi et al., PRL 95 177002 (2005)

IntroductionIntroduction

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Mo et al. PRL 90, 186403 (2003)Zhang et al. PRL 70, 1666 (1993)Panaccione et al. PRL 97 116401 (2006)Fujimori’s Lecture note

Coherent part

Incoherent part

U

DMFT cal.

VB-PES : V2 O3

Coherent peak in VBCoherent peak in VB--PESPES

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EF

O 2p band

3d

Central V atom

Coherent band

Neighboring site１．Intra-atomic multiplet

３．Hybridization betweenO 2p and V 3d orbital

２．Crystal Fields (C3v )

４．Screening from coherent bands

V

V*

ConfigurationConfiguration--interaction (CI) model interaction (CI) model

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Ground state：linear combination of 6 configurations

3d2 3d4L2

3d4LC

3d3L

3d3C

3d4C2

ParametersΔ= 6.0 eVU

= 4.5 eVUdc

= 6.5 eV10Dq

= 1.2 eVDtrg = - 0.05 eVV

= 2.9 eVV *

= 0.75 eVΔ* = 0.9 eVRc =0.8, Rv=0.9

U EF

O 2p band

UH

LH

CI modelCI model

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Taguchi et al.PRB 71, 155102 (2005)

*-Udc |

2p53d 2-Udc |

*

3d3L

3d3C

3d 2

2p53d3L

2p53d3C

|

f ›|

g ›

Calculation vs. Experiment Calculation vs. Experiment

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Introduction

NiO

Magnéli phaseTi4 O7

Summary

ContentsContents

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Van Veenendaal et al., PRL 70 2459 (1993)

2p53d9Lnon-local

multi-site cluster model

Ni 2p3/2 core level

NonNon--local screening local screening

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spin-fermion model: Bala et al., PRL 72 2600 (1994): PRB 61 13573 (2000)

LDA+DMFT: Ren et al., PRB 74 195114 (2006)Kunes et al., PRB 75 165115 (2007): PRL 99 156404 (2007)

Zhan-Rice doublet bound states

ZhangZhang--Rice doublet bound stateRice doublet bound state

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Parmigiani et al., J. Electr. Spectr. Rel. Phen. 98-99 287(1999)

Taguchi et al., PRL 100 206401 (2008)

A

BC

Ni 2p HXNi 2p HX--PESPES

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EF

O2p band

3d

Central Ni atom

ZR doubletbound state

2p core2p core--level HXlevel HX--PESPES

13/28Experiments: BL17SU @ SPring-8

Valence band PESValence band PES

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without 3d9Z

with 3d9Z

Experiments: BL17SU @ SPring-8

Resonant PES at Resonant PES at LL33

edgeedge

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Introduction

NiO

Magnéli phaseTi4 O7

Summary

ContentsContents

16/27T. Tonogai（PhD thesis）

4.0

3.5

3.0Valence

Metal

Insulator

Intermediatephase

MagnMagnééli phase: Tili phase: Ti44 OO77

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Abbate et al.,PRB51, 10150 (1995).

h = 45 eV

Kobayashi et al., Europhys. Lett. 59, 868 (2002).

Previous resultsPrevious results

extremely broad featuresextremely broad features

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Clear FermiClear Fermi--edgeedge

Metal Phase:Metal Phase:FermiFermi--Liquid stateLiquid state

Ti 2p resonant PESTi 2p resonant PES

Taguchi et al., cond-mat/0902.3701

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GaussianFermi-DiracSpectral function

Laser PESLaser PES

Taguchi et al., cond-mat/0902.3701

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mobile carriermobile carrier：：nn--typetype

Seebeck coefficient

O 1sconduction

band

LT

HT

IT

PESXAS

XASPES

PESXAS

EF

O 1s XAS & O 1s HXO 1s XAS & O 1s HX--PESPES

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O 1s

gap

conductionband

LT

HT

IT

valence band

PESXAS

XASPES

PESXAS

EF

Schematic picture Schematic picture

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Ti 2p HXTi 2p HX--PESPES

Taguchi et al., cond-mat/0902.3701

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*-Udc

|

2p53d0

-Udc

|

*

3d1L

3d1C

3d0

2p53d1L

2p53d1C

CT| g

› | f

›

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Ti4+ cluster（V* =0）

Ti 3+

Ti3+Ti4+

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ParametersΔ* = 0.3 eV

V

* = 0.26 eV

Ti4+ cluster

Ti 3+

coherent nature coherent nature

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NiO: All features in the VB and the core-level PES were reproduced well by extended CI model including ZR bound state screening effects.

Ti4 O7 : Resonant PES …. Fermi liquid state in HT phaseLaser PES …. Pseudo-gap feature in IT Ti 2p HX-PES …. This pseudo-gap feature is associated

with the coherent screening states.

SummarySummary

Further information on the nature of electronic state near EF can be obtained from the combination of HX-PES and other techniques.

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S. ShinA. ChainaniY. TakataY. IshidaT. Takeuchi

RIKEN/SPring-8Soft x-ray Lab.

T. IshikawaM. YabashiK. TamasakuY. Nishino

RIKEN/SPring-8Coherent x-ray Optics Lab.

NIMS S. Tsuda

Univ. of Tokyo

H. TakagiM. FujiwaraY. Nakamura

JASRI H. OhashiY. Senba

ISSPR. EguchiM. MatsunamiS. Watanabe

AcknowledgementsAcknowledgements

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Thank You very much for your attentionThank You very much for your attention