Spin susceptibility in superconductors without inversion symmetry

Abstract

In materials without spatial inversion symmetry, the spin degeneracy of the conduction electrons can be lifted by an antisymmetric spin-orbit coupling. We discuss the influence of this spin-orbit coupling on the spin susceptibility of such superconductors, with a particular emphasis on the recently discovered heavy Fermion superconductor CePt 3 Si. We find that, for this compound (with tetragonal crystal symmetry) irrespective of the pairing symmetry, the stable superconducting phases would give a very weak change of the spin susceptibility for fields along the c-axis and an intermediate reduction for fields in the basal plane. We also comment on the consequences for the paramagnetic limiting in this material. Contents 1. Introduction 2 2. The basic model and normal state Green's function 3 3. Superconducting phase 4 4. The static uniform spin susceptibility 6 5. Conclusions 8