Metal-insulator transition and superconductivity in a Ud= infinity extended Hubbard model

Abstract

A Ud= infinity extended Hubbard Hamiltonian (EHH) with a qualitatively accurate band structure, appropriate for a cubic lattice is investigated. At half filling the system undergoes a metal-insulator transition at a critical value of the charge transfer gap. Doping beyond half filling produces rapid metallisation of the insulating state. For all dopings considered, the effective quasiparticle-quasiparticle interaction is only attractive in the d channel with sinkxsinky symmetry. The effective interaction in all symmetry channels is suppressed on doping.