Full t-matrix approach to quasiparticle interference in non-centrosymmetric superconductors

Abstract

We develop the full t-matrix theory of quasiparticle interference (QPI) for non-centrosymmetric (NCS) superconductors with Rashba spin-orbit coupling. We give a closed solution for the QPI spectrum for arbitrary combination and strength of nonmagnetic (Vc) and magnetic (Vm) impurity scattering potentials in terms of integrated normal and anomalous Green's functions. The theory is applied to a realistic 2D model of the Ce-based 131- type heavy fermion superconductors. We discuss the QPI dependence on frequency, composition and strength of scattering and compare with Born approximation results. We show that the QPI pattern is remarkably stable against changes in the scattering model and can therefore give reliable information on the properties of Rashba-split Fermi surface sheets and in particular on the accidental nodal position of the mixed singlet-triplet gap function in NCS superconductors.