Electronic structure ofCuV2S4

The results of ab initio band-structure calculations and measurements of x-ray-emission valence spectra (XES) (Cu Lα, V K${\mathrm{\beta }}_5$, V Lα, S K${\mathrm{\beta }}_{1,3}$, S ${\mathit{L}}_{2,3}$) and x-ray-photoelectron valence-band and core-level spectra (XPS) of ${\mathrm{CuV}}_2$ ${\mathrm{S}}_4$ 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 ${\mathrm{CuV}}_2$ ${\mathrm{S}}_4$. The valence band is formed by Cu 3d, V 3d, V 4p, and S 3p states. Examination of the XES and XPS results and the calculated charge-density maps and densities of states indicates that the valences of both Cu and V are similar to those of their elemental solids. Calculations show a strong electron-phonon coupling in ${\mathrm{CuV}}_2$ ${\mathrm{S}}_4$ and the prospect of superconducting behavior has not been confirmed. © 1996 The American Physical Society.