Superconducting Properties ofA15Compounds Derived from Band-Structure Results

Abstract

Calculations of the electron-phonon interaction, $\lambda$, and $T_c$ are presented for ten different $A15\mathrm{}$ compounds, ${\mathrm{V}}_{3}X$ and ${\mathrm{Nb}}_{3}X$, $X=\mathrm{A}\mathrm{l},\mathrm{G}\mathrm{a},\mathrm{S}\mathrm{i},\mathrm{G}\mathrm{e},\mathrm{a}\mathrm{n}\mathrm{d}\mathrm{S}\mathrm{n}$. The calculated temperature-dependent magnetic susceptibility of ${\mathrm{Nb}}_3$Sn is also shown to be in good agreement with experiment. We argue that the low-temperature anomalies in many $A15\mathrm{}$ materials are related to the very sharp structure in the density of states near the Fermi energy found in our ab initio band-structure results.