Mixed-basis band-structure interpolation scheme applied to the fluorite-structure compounds ${\mathrm{NiSi}}_2$, ${\mathrm{AuAl}}_2$, ${\mathrm{AuGa}}_2$, and ${\mathrm{AuIn}}_2$

A mixed-basis band-structure interpolation scheme for fcc d-band metals has been extended to include fluorite-structure (${\mathrm{CaF}}_2$) compounds by incorporating more plane waves in the basis set. Since the fluorite and fcc structures belong to the same space group, the interpolation scheme originally developed for fcc d-band metals is also capable of generating fluorite band structures. The interpolation parameters for ${\mathrm{NiSi}}_2$, ${\mathrm{AuAl}}_2$, ${\mathrm{AuGa}}_2$, and ${\mathrm{AuIn}}_2$ have been determined by fitting nonrelativistic first-principles calculations using a nonlinear least-squares procedure. Good agreement with the first-principles results is obtained up to about 5 eV above the Fermi level for a basis set containing 39 plane waves and 5 d functions. The parameters for the intermetallic compounds containing Au were then adjusted to include the effects of spin-orbit splitting in the d bands and to improve the agreement of the calculated density of states with the results of photoelectron spectra. The adjusted d bands of ${\mathrm{AuAl}}_2$, ${\mathrm{AuGa}}_2$, and ${\mathrm{AuIn}}_2$ differ considerably from those calculated by first principles.