Nuclear magnetic relaxation rate in a noncentrosymmetric superconductor

Abstract

Noncentrosymmetric superconductors possess, in general, order parameters of mixed parity, i.e., the Cooper pairing state consists of spin-singlet and spin-triplet pairing components. We show that this property has important implications for the NMR and other measurable quantities in the heavy Fermion superconductor CePt3Si. The aspect of parity mixing explains the apparently contradicting observations of a Hebel-Slichter peak in the nuclear spin-lattice relaxation rate T-1(-1) and the presence of power law in the low-temperature behavior of certain physical quantities, indicating line nodes in the quasiparticle gap.