ELECTRON-ELECTRON CORRELATION THROUGH ELECTRON-PLASMON COUPLING IN HIGH-T_c SUPERCONDUCTORS

A model for high T_c superconductivity is considered. The Cu d_x²-y² electrons correlate by means of polarization-plasmon interaction. We show that when the plasmon energy approaches to the energy difference of the two bands of Cu d_x²-y², a resonant-enhanced interaction between the electrons can be realized. In this model the oxygen vacancies are responsible for the high-T_c superconductivity to which the plasmon frequency is mainly related.