Chiral detection of Majorana bound states at the edge of a quantum spin Hall insulator

TL;DR

This paper proposes a novel hybrid device combining quantum spin Hall and quantum anomalous Hall insulators for robust detection of Majorana bound states, demonstrating enhanced immunity to disorder through 2D transport simulations.

Contribution

It introduces a new hybrid setup for chiral electron injection into Majorana bound states and explores a previously unexamined phase space region for improved detection.

Findings

The proposed setup shows strong resilience against disorder effects.

Simulations indicate clear contrast in Majorana detection with and without QAH region.

Enhanced immunity to magnetic and Rashba fields in the hybrid device.

Abstract

A hybrid setup consisting of a superconductivity-proximitized quantum spin Hall (QSH) insulator and a quantum anomalous Hall (QAH) insulator is proposed for chiral injection of electrons into the Majorana bound state (MBS). An unexplored region of the phase space involving the exchange field induced boost of the helical edge state is then proposed for the detection of the MBS. 2-D transport simulations of our proposed setup is compared with the corresponding setup in the absence of the QAH region, when moderate disorder and a small but finite bulk out-of-plane magnetic field and a Rashba field are included. The remarkable contrast between the two results demonstrates the possibility for an unprecedented immunity from disorder-induced masking of the MBS detection in our proposed setup.