Competition between Triplet Superconductivity and Kondo Effect

Abstract

The Kondo effect strongly depends on spin and orbital degrees of freedom of Cooper pairs. We focus on the Kondo effect in a p x +i p y -wave superconductor with a full energy gap. The numerical renormalization study shows that the ground state is always a spin doublet for a S imp =1/2 local spin and that it is always a spin singlet for S imp =1. The latter is due to uniaxial spin anisotropy of the Cooper pair. We also compare these results with a case of the d x 2 - y 2 +i d x y -wave superconductivity having the same energy-gap structure.