Electronic charge density and bonding inV3Si

A self-consistent pseudopotential approach using a mixed-basis set (plane waves plus localized orbitals) is used to obtain the valence charge density and electronic structure of ${\mathrm{V}}_3$Si. The calculated charge density is compared with the results determined from x-ray measurements. Both the experimental and calculated charge densities show a piling up of charge between V atoms along the V-V chain. To determine the bonding of this compound arising from the various interactions, V-V, Si-Si, and V-Si, we have also calculated the charge density for ${\mathrm{V}}_3^{*}$ (chain only) and Si (bcc). Taking the difference between the charge density of ${\mathrm{V}}_3$Si and that of the ${\mathrm{V}}_3^{*}$ and Si combined, we examined the charge transfer coming from the V-Si interaction. The resulting bonding is covalent between V atoms along the chains and metallic between V and Si. The $E$ vs $k$ dispersion from $\Gamma$ to $X$ was examined and found to compare well with the recent angle-resolved photoemission data of Aono, Himpsel, and Eastman.