Tight-binding study of the electron-phonon interaction in bcc transition metals and alloys.

Abstract

The tight-binding method has been used to study the electron-phonon interaction in several bcc transition metals and alloys. Slater-Koster fits to self-consistent, scalar-relativistic, augmented-plane-wave band calculations have been employed and scaling relations were used in determining gradients of the tight-binding matrix elements. The two-center integral parameters were adjusted for alloys in a way which explicitly accounts for the change in lattice constant. Results for 3d and 4d transition-metal elements are in good agreement with rigid-muffin-tin calculations. In addition, the electron-phonon coupling in ${\mathrm{Mo}}_{\mathrm{x}}$${\mathrm{Nb}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$ is evaluated from densities of states calculated by the coherent-potential approximation. The measured variation of the superconducting transition temperature as a function of x is reproduced well by this calculation.