Interaction-induced zero-energy pinning and quantum dot formation in Majorana nanowires

TL;DR

This paper demonstrates that electrostatic interactions in realistic three-dimensional models suppress Majorana oscillations and induce quantum dot states in nanowires, aiding the interpretation of experimental observations.

Contribution

It introduces a realistic 3D electrostatic model showing how interactions lead to zero-energy pinning and quantum dot formation in Majorana nanowires.

Findings

Interaction suppresses Majorana oscillations.

Quantum dot states form near Majoranas.

Results align with recent experimental data.

Abstract

Majorana modes emerge in non-trivial topological phases at the edges of some specific materials, like proximitized semiconducting nanowires under a external magnetic field. Ideally, they are non-local states that are charge neutral superpositions of electrons and holes. However, in nanowires of realistic length their wave functions overlap and acquire a finite charge that, under certain circumstances, makes them susceptible to interactions, specifically with the image charges that arise in the electrostatic environment. Considering a realistic three-dimensional model of the dielectric surroundings, here we show that this interaction leads to a suppression of the Majorana oscillations predicted by simpler theoretical models, and to the formation of low-energy quantum dot states that interact with the Majorana modes. Both features are observed in recent experiments on the detection of Majoranas and could thus help to properly characterize them.