Antiferromagnetic singlet pairs, high-frequency phonons, and superconductivity

Abstract

The properties of a model of electrons interacting through an on-site Hubbard repulsion U, and coupled to intersite lattice vibrations, are discussed. It is argued that the antiferromagnetic singlet pairs induced by U will condense into a superconducting state in the presence of coupling to high-frequency phonons, or, equivalently, that an on-site U strongly enhances the electron-phonon coupling giving rise to superconductivity. It is proposed that this model describes the essential features of the high-${T}_{c}$ oxide superconductors.