Majorana Coupling and Kondo Screening of Localized Spins

Abstract

We perform a theoretical analysis of the fate of the local magnetic moment of a quantum dot coupled to  a normal metallic lead  and  a topological superconducting wire hosting Majorana modes at the ends. By means of simple analytical tools and numerical renormalization group calculations, we show that the proximity of the Majorana mode reduces the magnetic moment from 1/4, characteristic of a free spin 1/2, to 1/16. Coupling to the normal lead then causes the Kondo effect, such that the magnetic moment is fully screened below the Kondo temperature. The latter is vastly increased for strong coupling to Majorana mode.