Spin-resolved thermal signatures of Majorana-Kondo interplay in double quantum dots

TL;DR

This paper theoretically explores how Majorana zero modes influence thermoelectric transport in a double quantum dot system, revealing fractional conductance, modified laws, and unique spin Seebeck effects due to Majorana-Kondo interplay.

Contribution

It introduces a detailed analysis of Majorana-induced effects on thermoelectric properties in a double quantum dot with Kondo correlations, using numerical renormalization group methods.

Findings

Majorana modes cause half-suppression of the second Kondo stage.

Fractional charge and heat conductances are observed.

Modified Wiedemann-Franz law and unique spin Seebeck effects are identified.

Abstract

We investigate theoretically the thermoelectric transport properties of a T-shaped double quantum dot side-coupled to a topological superconducting nanowire hosting Majorana zero-energy modes. The calculations are performed using the numerical renormalization group method focusing on the transport regime, where the system exhibits the two-stage Kondo effect. It is shown that the leakage of Majorana quasiparticles into the double dot system results in a half-suppression of the second stage of the Kondo effect, which is revealed through fractional values of the charge and heat conductances and gives rise to new resonances in the Seebeck coefficient. The heat conductance is found to satisfy a modified Wiedemann-Franz law. Finally, the interplay of Majorana-induced interference with strong electron correlations is discussed in the behavior of the spin Seebeck effect, a unique feature of the considered setup.