Spin-resolved interference due to Majorana state on interface between normal and superconducting leads

TL;DR

This paper explores how Majorana quasiparticles influence spin-dependent interference and transport in a quantum dot system interfaced with topological superconductors, revealing unique signatures and interplay with Kondo effects.

Contribution

It provides a detailed analysis of spin-selective interference patterns caused by Majorana states and compares them with a simplified toy model, highlighting novel spin-dependent signatures.

Findings

Majorana states induce spin-selective interference patterns.

Distinct signatures for different spin components are identified.

Interplay between Majorana and Kondo effects at zero energy is characterized.

Abstract

We investigate the subgap spectrum and transport properties of the quantum dot placed on interface between metallic and superconducting leads and additionally side-coupled to the edge of topological superconducting (TS) chain, hosting the Majorana quasiparticle. Due to chiral nature of the Majorana states only one spin component, say $\uparrow$, of the quantum dot electrons is directly hybridized with the TS wire. We study the spin-selective interferometric patterns driven by the Majorana quasiparticle. The proximity induced on-dot pairing effectively transmits the interference onto both spin components, but each of them is characterized by completely different (even opposite) signatures. To explain their origin we confront our results with the toy model, where TS chain is replaced by the usual quantum and the tunneling of $\downarrow$ electrons is prohibited. We also address unique interplay of the Majorana and Kondo features, both appearing at zero energy.