PAIRING SYMMETRY AND ISOTOPE EFFECT IN HIGH-TEMPERATURE SUPERCONDUCTOR

Abstract

It is demonstrated that various forms of the 2D pairing parameter lead to an unusual type of the isotope effect quite distinct from the ordinary BCS behavior. The special form of the local pairing in the real space is considered in order to better use the density of states singularities and explain critical lattice distortion for high-temperature superconductors. The isotope effect is also studied for the recently suggested weak coupling theory with the order parameter antisymmetric in energy with respect to Fermi level.