Fundamental Properties and Origin of the High-Tc Cuprate Superconductors: Development of Concepts

Abstract

After a review of the fundamental properties of the high-Tc cuprate superconductors, we evaluate and study the major parameters of these compounds. In this approach, we consider the attractive interaction is due to the phonons at low temperature, but at high temperature it is related to the magnetic excitations. Analytical expressions for the coherence length , the isotope coefficient and the superconducting gap ratio R = 2 (0) /k B T c are obtained for the case where the Fermi level is close to the van Hove singularity. This model explains simultaneously high Tc, large gap energy (0), short coherence length and small values of the isotope coefficient. Our theoretical values are in a good agreement with experimental results.