Kondo and Majorana signatures near the singlet-doublet quantum phase transition

Abstract

We study the low energy spectrum of a correlated quantum dot embedded between the normal conducting and superconducting reservoirs and hybridized with the topological superconducting nanowire, hosting the Majorana end-modes. We investigate the leaking Majorana quasiparticle and inspect its interplay with the proximity induced on-dot pairing and correlations. In particular, we focus on the subgap Kondo effect near the quantum phase transition/crossover from the spinfull (doublet) to the spinless (BCS-type singlet) configurations. Treating the correlations perturbatively and within the NRG approach we study its signatures observable in the Andreev (particle-to-hole conversion) tunneling spectroscopy. We find, that the leaking Majorana mode has a spin-selective influence on the subgap Kondo effect.