Effect of topological length on Bound states signatures in a Topological nanowire

TL;DR

This paper proposes a protocol to distinguish Majorana bound states from trivial states in nanowires by altering the topological region length and analyzing tunneling conductance signatures, aiding in topological qubit verification.

Contribution

It introduces a novel protocol that uses topological length variation to differentiate topological zero-bias peaks from trivial ones in nanowire systems.

Findings

Topological ZBP remains robust at zero bias during the protocol.

Trivial ZBP splits into two peaks at finite bias under the protocol.

The method effectively distinguishes topological from trivial bound states.

Abstract

Majorana bound states (MBS) at the end of nanowires have been proposed as one of the most important candidate for the topological qubits. However, similar tunneling conductance features for both the MBS and Andreev bound states (ABS) have turned out to be a major obstacle in the verification of the presence of MBS in semiconductor-superconductor heterostructures. In this article, we use a protocol to probe properties specific to the MBS and use it to distinguish the topological zero-bias peak (ZBP) from a trivial one. For a scenario involving quantized ZBP in the nanowire, we propose a scheme wherein the length of the topological region in the wire is altered. The tunneling conductance signatures can then be utilized to gauge the impact on the energy of the low-energy states. We show that the topological and trivial ZBP behave differently under our protocol, in particular, the topological ZBP remains robust at zero bias throughout the protocol, while the trivial ZBP splits into two peaks at finite bias. This protocol probes the protection of near zero energy states due to their separable nature, allowing us to distinguish between topological and trivial ZBP.