Influence of local symmetry on the electron-phonon coupling in perovskites

Abstract

The Hopfield factor (electronic part of the electron-phonon coupling constant) is calculated in the Rigid-Muffin-Tin approximation (RMTA) for several perovskite high-Tc superconductors. Calculations were performed in the conventional “spherical” approximation, as well as taking into account proper local symmetry. It is shown that the layered perovskite crystal symmetry generally favors strong electron-phonon interaction on copper site. We also estimate some for non-RMTA effects.