Superconducting Instability Temperature of a Non-Centrosymmetric System

Abstract

We discuss a direct effect of the energy band splitting due to the antisymmetric spin–orbit coupling on the superconducting phase transition. Employing the square lattice tight-binding model we show a significant contribution of the spin-split energy band to the pair-breaking effect in the weakand intermediate-coupling non-centrosymmetric superconductors. We establish a general tendency of the spin–orbit coupling to suppress the critical temperature of the spin singlet and triplet states. For the weak-coupling systems we report a possible development of sharp maxima of the critical temperature for the band fillings which support the spin–orbit coupling induced Fermi surface singularities of the density of states. We note that the initial suppression of the most stable triplet state becomes comparable to the suppression of other triplet states in the intermediate-coupling regime of superconductivity.