Orbital symmetry and electron correlation in NaxCoO2.
Measurements of polarization-dependent soft x-ray absorption reveal that the electronic states determining the low-energy excitations of NaxCoO2 have predominantly a(1g) symmetry with significant O 2p character. In contrast to the prediction of band theory, doping-dependent O 1s x-ray absorption shows a large transfer of spectral weight, providing spectral evidence for strong electron correlations of the layered cobaltates. We also found that NaxCoO2 exhibits a charge-transfer electronic character rather than a Mott-Hubbard character.
Wu
W B
WB
National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
Huang
D J
DJ
Okamoto
J
J
Tanaka
A
A
Lin
H-J
HJ
Chou
F C
FC
Fujimori
A
A
Chen
C T
CT