A topological flux trap: Majorana bound states at screw dislocations

TL;DR

This paper proposes a novel method to realize Majorana bound states in trivial superconductors by trapping vortices at screw dislocations, creating a topological system without complex heterostructures.

Contribution

It demonstrates that vortex-dislocation pairs in trivial superconductors can host Majorana states, offering a new route for topological quantum computing.

Findings

Vortices with even flux quanta at screw dislocations form topological sub-systems.

Majorana bound states appear at surface terminations of the vortex-dislocation pair.

Topological transition driven by band inversion in vortex bound states.

Abstract

The engineering of non-trivial topology in superconducting heterostructures is a very challenging task. Reducing the number of components in the system would facilitate the creation of the long-sought Majorana bound states. Here, we explore a route toward emergent topology in a trivial superconductor without a need for other proximitized materials. Specifically, we show that a vortex hosting an even number of flux quanta is capable of forming a quasi-one-dimensional topological sub-system that can be mapped to the Kitaev wire, if the vortex is trapped at a screw dislocation. This crystallographic defect breaks inversion symmetry and thereby threads a local spin-orbit coupling through the superconductor. The vortex-dislocation pair in the otherwise trivial bulk can harbor a pair of Majorana bound states located at the two surface terminations. We explain the topological transition in terms of a band inversion in the Caroli-de Gennes-Matricon vortex bound states and discuss favorable material parameters.