Theory of high-Tc superconducting cuprates based on experimental evidence

A model of superconductivity in layered high-temperature superconducting cu prates is proposed, based on the extended saddle point singularities ill th e electron spectrum, weak screening of the Coulomb interaction and phonon-m ediated interaction between electrons plus a small short range repulsion of Hund's, or spin-fluctuation, origin. This permits to explain the large val ues of Tc, features of the isotope effect on oxygen and copper, the existen ce of two types of the order parameter, the peak in the inelastic neutron s cattering, the positive curvature of the upper critical field, as function of temperature etc.