Linear augmented Slater-type-orbital study of Au–5d-transition-metal alloying

Abstract

We have used density-functional theory with an augmented Slater-type-orbital basis to calculate the heat of formation and crystal structure for the 5d-transition-metal–gold alloys AuLu through AuPt. The crystal structures considered were CsCl, CuAuI, γ-CuTi, ${\mathrm{MoSi}}_2$, ${\mathrm{Au}}_2$ ${\mathrm{Nb}}_3$, ${\mathrm{Cu}}_3$Au, ${\mathrm{Cr}}_3$Si, and ${\mathrm{AlB}}_2$, though not all structures were calculated for each compound. There are no experimental values for the heats but our results are consistent with known phase diagrams. In several instances we find suppression of a phase at 50%-50% by another off 50%-50%. We have also calculated the charge transfer using Mulliken and Wigner-Seitz sphere counts. These do not follow electronegativity trends but are consistent with calculated initial-state core-level shifts and Mössbauer isomer shifts (obtained from the calculated contact density).