Transition Temperature Enhancement Due to Aniferromagnetic Fluctuations in High-T_C Oxide Superconductors

Abstract

It is shown theoretically that antiferromagnetic fluctuations enhance the superconducting transition temperature drastically for the anisotropic pairing state, e.g. the d-wave-like pairing, because of the pseudo-gap formation due to the fluctuations.Within the renormalized random phase approximation (RRPA), an imperfect nesting model for a two-dimensional square lattice is investigated. Implication of the results is discussed in connection with the high-T_C oxide superconductors.