Superconducting Properties of A15 Compounds Derived from Band-Structure Results

Calculations of the electron-phonon interaction, λ, and Tc are presented for ten different $A15$ compounds, V₃X and Nb₃X, $X=Al,{{0ex}{0ex}}Ga,{{0ex}{0ex}}Si,{{0ex}{0ex}}Ge,{{0ex}{0ex}}and{{0ex}{0ex}}Sn$. The calculated temperature-dependent magnetic susceptibility of ${Nb}₃$Sn is also shown to be in good agreement with experiment. We argue that the low-temperature anomalies in many $A15$ 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.