Electron-phonon interaction is considered within the framework of the fluctuating valence of Cu atoms. Anderson's lattice Hamiltonian is suitably modified to take this into account. Using Green's function technique the possible quasiparticle excitations are determined. The quantity 2∆k(0)/kBTc is calculated for Tc = 40 K. The calculated values are in good agreement with the experimental results.
S. V. Vettoor and Dr. V . M. Nandakumaran, “ELECTRON-PHONON INTERACTION WITHIN THE FRAMEWORK OF THE FLUCTUATING VALENCE OF COPPER ATOMS—A THEORETICAL MODEL FOR HIGH TEMPERATURE SUPERCONDUCTIVITY”, Modern Physics Letters B, vol. 4, pp. 325–331, 1990.