Van Hove excitons and high-Tc superconductivity. II. Toward a calculation of Tc

Abstract

For pt.I see ibid., vol.1, p.8911 (1989). Tc is estimated for the excitonic model developed in an earlier paper. It is shown that, by inclusion of transverse phonon coupling and retardation effects, the high values of Tc and small isotope effects can readily be understood. The connection of the excitons with covalent bond formation is stressed, as well as the relation of high-Tc oxide superconductors to other exotic superconducting materials.