Interacting topological phases in multiband nanowires

TL;DR

This paper investigates how interactions and symmetry-breaking perturbations affect the stability of topological phases supporting Majorana modes in multiband nanowires, providing insights relevant for experimental realization.

Contribution

It introduces a detailed analysis of the phase diagram near a multicritical point in multiband nanowires, highlighting the effects of interactions on topological phases.

Findings

Identification of a multicritical point with coupled Majorana chains

Interactions influence the stability of topological phases

Results inform experimental approaches to Majorana nanowires

Abstract

We show that semiconductor nanowires coupled to an s-wave superconductor provide a playground to study effects of interactions between different topological superconducting phases supporting Majorana zero-energy modes. We consider quasi-one dimensional system where the topological phases emerge from different transverse subbands in the nanowire. In a certain parameter space, we show that there is a multicritical point in the phase diagram where the low-energy theory is equivalent to the one describing two coupled Majorana chains. We study effect of interactions as well as symmetry-breaking perturbations on the topological phase diagram in the vicinity of this multicritical point. Our results shed light on the stability of the topological phase around the multicritical point and have important implications for the experiments on Majorana nanowires.