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2005 APCTP Summer School on Strongly Correlated Electron SystemsAsia Pacific Center for Theoretical Physics & POSTECH, Pohang, Korea
Photoemission spectroscopy of Photoemission spectroscopy of transitiontransition--metal oxides, metal oxides,
highhigh--temperature superconductors, temperature superconductors, and magnetic semiconductorsand magnetic semiconductors
Atsushi FUJIMORI University of Tokyo
Phase diagram of a correlated electron systemPhase diagram of a correlated electron system
1 electron/atomT = 0 K
SpinSpin--chargecharge--orbital coupling andorbital coupling andGiant response of correlated electron systemsGiant response of correlated electron systems
Correlated electron systems/Correlated electron systems/Complex materials Complex materials
La2-xSrxCuO4
Ga1-xMnxAs
AngleAngle--Resolved Photoemission SpectroscopyResolved Photoemission SpectroscopyARPESARPES
kx
ky Fermi sruface
EF
below EF
k
Band dispersion
Fermi surfaces of strongly correlated systemFermi surfaces of strongly correlated system
A. Damascelli, et al., PRL ‘00
Fermi surface of Sr2RuO4from ARPES
Fermi surface of Sr2RuO4 from de Haas-van Alfven effect
C. Bergemann et al., Phys. Rev. Lett. ‘00
Synchrotron radiationSynchrotron radiation
electron
acceleration
velocitySR
Characteristics
• tunable energy
• fixed/variable polarization
• high intensity
• low emittance
electron
SR from bend magnet
electron
SR from undulatorSpring-8 Home Page
Synchrotron radiationSynchrotron radiation
Characteristics
• tunable energy
• fixed/variable polarization
• high intensity
• low emittance
electron
acceleration
velocitySR
electron
electron
SR from bend magnet
SR from undulator
放射光の特徴
・波長連続可変
・偏光性
・大強度
・指向性
SR from bend magnet
sun light
medical x-ray
rotating anode
wiggler
soft x-ray udulator
Spring-8 undulatorlong undulator
Photon energy (eV)
Wave length (nm)
VIS VUV X
IR UV SX
Brilli
ance
(pho
tons
/sec
/mm
2/m
drad
2 0.
1% b
and
pass
)
Spring-8 Home Page
OutlineOutline
• Transition-metal oxides– Mott insulators– Metal-insulator transitions
• High-temperature superconductors• Magnetic semiconductors
General references: M. Imada, A. Fujimori, and Y. Tokura: Metal-Insulator Transitions, Rev. Mod. Phys. 70 (1998)
1039.N. Tsuda, K. Nasu, A. Fujimori and K. Siratori: Electronic Conduction in Oxides (Springer-
Verlag, Berlin, 2000).T. Mizokawa, A. Fujimori, J. Okabayashi and O. Rader: Photoemission Spectroscopy of Diluted Mn in and on Solids, J. Electron Spectrosc. Relat. Phenom. 136 (2004) 21.