Density of states of disordered topological superconductor-semiconductor hybrid nanowires

TL;DR

This paper numerically investigates how disorder affects the density of states in topological superconductor-semiconductor nanowires, revealing suppression yet persistence of Majorana-related features despite strong disorder.

Contribution

It provides a detailed numerical analysis of disorder effects on the density of states and compares with SCBA theory, highlighting the robustness of Majorana signatures.

Findings

Disorder suppresses the zero-bias peak associated with Majorana modes.

Some zero-bias peaks persist even when the topological gap vanishes.

Disorder impacts topological and trivial phases differently.

Abstract

Using Bogoliubov-de Gennes (BdG) equations we numerically calculate the disorder averaged density of states of disordered semiconductor nanowires driven into a putative topological p-wave superconducting phase by spin-orbit coupling, Zeeman spin splitting and s-wave superconducting proximity effect induced by a nearby superconductor. Comparing with the corresponding theoretical self-consistent Born approximation (SCBA) results treating disorder effects, we comment on the topological phase diagram of the system in the presence of increasing disorder. Although disorder strongly suppresses the zero-bias peak (ZBP) associated with the Majorana zero mode, we find some clear remnant of a ZBP even when the topological gap has essentially vanished in the SCBA theory because of disorder. We explicitly compare effects of disorder on the numerical density of states in the topological and trivial phases.