Angle-resolved photoemission study of the MX-chain compound [Ni(chxn)(2)Br]Br(2): spin-charge separation in hybridized d-p chains.
We report on the results of angle-resolved photoemission experiments on a quasi-one-dimensional (1D) MX-chain compound [Ni(chxn)2Br]Br2, which shows a gigantic nonlinear optical effect. A "band" having about 500 meV energy dispersion is found in the first half of the Brillouin zone, but disappears at kb/pi approximately 1/2. These spectral features are well reproduced by the d-p chain model with a small charge-transfer energy Delta compared with that of 1D Cu-O compounds. We propose that this smaller Delta is the origin of the absence of clear spin-charge separation in the photoemission spectra and the strong nonlinear optical effect.
Fujimori
Shin-ichi
S
Synchrotron Radiation Research Center, Japan Atomic Energy Research Institute, SPring-8, Mikazuki, Hyogo 679-5148, Japan.
Ino
Akihiro
A
Okane
Testuo
T
Fujimori
Atsushi
A
Okada
Kozo
K
Manabe
Toshio
T
Yamashita
Masahiro
M
Kishida
Hideo
H
Okamoto
Hiroshi
H