Aharonov-Bohm interference as a probe of Majorana fermions

TL;DR

This paper proposes using Aharonov-Bohm interference in a Kitaev chain ring to detect Majorana fermions, providing a robust transport signature that can distinguish them from other phenomena.

Contribution

It introduces a computational approach analyzing magnetic field dependence of transport in a Kitaev ring as a novel signature for Majorana bound states.

Findings

Transport signatures are robust against weak disorder.

Magnetic field dependence reveals Majorana states.

Aharonov-Bohm interference can distinguish Majorana modes.

Abstract

Majorana fermions act as their own antiparticle, and they have long been thought to be confined to the realm of pure theory. However, interest in them has recently resurfaced, as it was realized through the work of Kitaev that some experimentally accessible condensed matter systems can host these exotic excitations as bound states on the boundaries of 1D chains, and that their topological and non-abelian nature holds promise for quantum computation. Unambiguously detecting the experimental signatures of Majorana bound states has turned out to be challenging, as many other phenomena lead to similar experimental behaviour. Here, we computationally study a ring comprised of two Kitaev model chains with tunnel coupling between them, where an applied magnetic field allows for Aharonov-Bohm interference in transport through the resulting ring structure. We use a non-equilibrium Green's function technique to analyse the transport properties of the ring in both the presence and absence of Majorana zero modes. Further, we show that these results are robust against weak disorder in the presence of an applied magnetic field. This computational model suggests another signature for the presence of these topologically protected bound states can be found in the magnetic field dependence of devices with loop geometries.