Electronic structure and superconductivity of fcc Cr

Abstract

Results of self-consistent electronic structure calculations are reported for metastable fcc Cr metal. Unlike the case of bcc Cr which has $E_F$ at a minimum in the density of states (DOS), the DOS at $E_F$ in fcc Cr is at a peak making this one of the higher-DOS metals with the fcc structure (e.g., comparable with that of Ni and Pt). A calculated Stoner factor of 0.82 indicates that ferromagnetic ordering is not expected. Calculations of the electron-phonon coupling parameter $\lambda$ and superconducting transition temperature $T_c$ were made using the rigid-ion approximation and strong-coupling theory with various estimates of the (unknown) phonon contribution. We conclude that $T_c\text{'}\mathrm{s}\approx 2.5$ K are reasonable, although they are substantially smaller than the $T_c\approx 10$ K derived from measurements on Au-Cr-Au sandwiches.