Proposal for the detection and braiding of Majorana fermions in a quantum spin Hall insulator

TL;DR

This paper proposes a method to detect Majorana fermions in a quantum spin Hall insulator using a quantum dot and magnetic field, and discusses how to braid them for non-Abelian statistics demonstration.

Contribution

It introduces a setup for creating and detecting Majorana zero-modes in quantum spin Hall insulators and suggests a way to braid them via edge coupling.

Findings

Detection of Majorana zero-modes as zero-bias conductance peaks.

Proposal of a constriction to enable braiding of Majorana fermions.

Observation of non-Abelian statistics potential in the system.

Abstract

We show how a quantum dot with a ballistic single-channel point contact to a superconductor can be created by means of a gate electrode at the edge of a quantum spin Hall insulator (such as an InAs/GaSb quantum well). A weak perpendicular magnetic field traps a Majorana zero-mode, so that it can be observed in the gate-voltage-averaged differential conductance <dI/dV> as a 4e^2/h zero-bias peak above a (2/3{\pi}^2 - 4)e^2/h background. The one-dimensional edge does not permit the braiding of pairs of Majorana fermions, but this obstacle can be overcome by coupling opposite edges at a constriction, allowing for a demonstration of non-Abelian statistics.