Continuous unitary transformation approach to the Kondo-Majorana interplay

TL;DR

This paper investigates the competition between Majorana zero modes and Kondo resonance in a quantum dot system using continuous unitary transformations, revealing how coupling affects exchange interactions and the Kondo temperature.

Contribution

It introduces the application of the continuous unitary transformation method to analyze the interplay between Majorana modes and Kondo physics in hybrid quantum dot systems.

Findings

Coupling to the topological chain modifies effective exchange interactions.

The Kondo temperature is affected by the Majorana mode leakage.

The CUT technique provides insights into the competition dynamics.

Abstract

We analyze a setup composed of a correlated quantum dot (QD) coupled to one metallic lead and one end of topological chain hosting a Majorana zero mode (MZM). In such a hybrid structure, a leakage of the MZM into the region of the QD competes with the Kondo resonance appearing as a consequence of the spin-exchange interactions between the dot and the lead. In the work, we use the nontrivial technique called the continuous unitary transformation (CUT) to analyze this competition. Using the CUT technique, we inspect the influence of the coupling between the QD and the chain on effective exchange interactions and calculate the resultant Kondo temperature.