Majorana coupling and Kondo screening of localized spins

Abstract: We perform a theoretical analysis of the fate of 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 Majorana mode reduces the magnetic moment from $1/4$, characteristic of a free spin $1/2$, to $1/16$. The 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.