ELECTRONIC-STRUCTURE OF CUV2S4

The results of ab initio band-structure calculations and measurements of x-ray-emission valence spectra (XES) (Cu L alpha, V K beta(5), V L alpha, S K beta(1,3), S L(2,3)) and x-ray-photoelectron valence-band a nd core-level spectra (XPS) of CuV2S4 thiospinel are presented. It is found that a peak in valence-conduction bands close to Fermi level is formed by V 3d states, which provide the metallic properties of CuV2S4 . The valence band is formed by Cu 3d, V 3d, V 4p, and S 3p states. Ex amination of the XES and XPS results and the calculated charge-density maps and densities of states indicates that the valences of both Cu a nd V are similar to those of their elemental solids. Calculations show a strong electron-phonon coupling in CuV2S4 and the prospect of super conducting behavior has not been confirmed.