[3] Univ Cattolica, Ist Nazl Fis Mat, I-25121 Brescia, Italy
[4] Univ Cattolica, Dipartimento Matemat & Fis, I-25121 Brescia, Italy
[5] Deutsch Res, Mountain View, CA 94040 USA
来源:
PHYSICAL REVIEW B
|
1998年
/
57卷
/
16期
关键词:
D O I:
10.1103/PhysRevB.57.10175
中图分类号:
T [工业技术];
学科分类号:
08 ;
摘要:
Resonant photoemission experiments at the Co 3p-->3d absorption threshold are used to identify the correlated satellites in the one-electron removal spectrum of the valence band of the two-dimensional Ising antiferromagnet K2CoF4. In addition, x-ray photoelectron spectra of the core levels, interpreted by a configuration-interaction impurity-cluster model, are reported. The estimated charge transfer Delta and the Mott-Hubbard U charge fluctuations pose K2CoF4 in the Mott-Hubbard region of the Zaanen-Sawatzky-Allen diagram. The values of Delta and U are also used to estimate the superexchange parameter J by considering a metal-ligand-metal three-center model. The results for K2CoF4 are compared to those obtained for CoO and the effect of Delta on the photoemission spectral features and on the magnitude of J are discussed.