Electron-phonon interaction in Ba2 YCu3O7

Abstract

A realistic tight-binding theory, based on the energy-band results of Mattheiss and Hamann, is applied to study the electron-phonon interaction in ${\mathrm{Ba}}_2$ ${\mathrm{YCu}}_3$ ${\mathrm{O}}_7$. In contrast to previous results for the 40-K superconductor ${\mathrm{La}}_{2-x}{(\mathrm{B}\mathrm{a},\mathrm{S}\mathrm{r})}_x\mathrm{Cu}{\mathrm{O}}_4$, the theoretical values for the electron-phonon coupling are much too small to yield superconducting transition temperatures in the 90-K range.