Theory of high-T-c 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 in the electron spectrum, weak screening of the Coulomb interaction and phonon-me diated interaction between electrons plus a small short-range repulsion of Hund's, or spin-fluctuation, origin. This permits to explain the large valu es of T-c, 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.