A model for superconducting Cu oxides: The oxygen p band hybridized with d(3z 2-r 2) of Cu

Abstract

We assume that excess holes in high T c YBaCuO and related oxide superconductors enter in the p z band of oxygen atoms situated right above Cu(II). Representing holes localized at Cu(II) by the antiferromagnetic Heisenberg model and introducing a ferromagnetic coupling between spins of excess holes and those at Cu(II) sites, we study the interaction between two excess holes by computing the ground state energy of a system of finite number of atoms. The condition for obtaining an attractive interaction between the excess holes is discussed.