Robust topological phase in proximitized core-shell nanowires coupled to multiple superconductors

TL;DR

This paper demonstrates that core-shell nanowires with multiple superconductors and prismatic geometry can host robust topological superconductivity, with enhanced stability and reduced critical fields for Majorana states.

Contribution

It introduces a model showing how multiple superconductors and phase differences improve topological phase stability in nanowires.

Findings

Finite phase differences enhance topological stability.

Orbital effects are suppressed by prismatic geometry.

Critical magnetic field for topological transition is reduced.

Abstract

We consider core-shell nanowires with prismatic geometry contacted with two or more superconductors in the presence of a magnetic field applied parallel to the wire. In this geometry, the lowest energy states are localized on the outer edges of the shell, which strongly inhibits the orbital effects of the longitudinal magnetic field that are detrimental to Majorana physics. Using a tight-binding model of coupled parallel chains, we calculate the topological phase diagram of the hybrid system in the presence of non-vanishing transverse potentials and finite relative phases between the parent superconductors. We show that having finite relative phases strongly enhances the stability of the induced topological superconductivity over a significant range of chemical potentials and reduces the value of the critical field associated with the topological quantum phase transition.