Electronic charge density and bonding in two NiAs-type solids: TiS and VS

The electronic band structure and charge densities for two transition metal monosulfides TiS and VS, with the NiAs-type structure have been calculated using the band theoretical Green's function technique. The results of these calculations are interpreted in terms of chemical bonding and stabilization effects in the solid. It is found that the charge density of the transition metal d-like electrons is maximized in the direction through centers of triangular faces of the octahedrally coordinated sulfur atoms, rather than along the c axis between adjacent metal atom layers, a distribution which was originally believed to stabilize the NiAs-type structure