Unitary Limit of Spin-orbit scattering in two-dimensional s- and d-wave superconductors

Abstract

Non-magnetic impurities affect the paramagnetic response of superconductors via the associated spin-orbit interaction which, when the non-magnetic impurity is close to the unitary limit, must be treated beyond the classical Born approximation. Here the Zeeman response of two-dimensional s- and d-wave superconductors is calculated within the self-consistent T-matrix formulation for both impurity and spin-orbit scatterings. It is shown that at the unitary limit, for which the spin-orbit scattering is maximum, the spin-up and spin-down channels becomes decoupled implying full Zeeman splitting of the quasiparticle excitations. These results could be used to test the unitary scattering hypothesis in high-Tc superconductors.