Identifying Majorana vortex modes via non-local transport

TL;DR

This paper proposes a nonlocal transport measurement method to identify Majorana vortex modes in 2D topological superconductor systems, providing a clear distinction from ordinary fermionic modes even when vortex core modes hybridize.

Contribution

It introduces a novel nonlocal transport protocol to detect Majorana vortex modes, enhancing identification accuracy in hybridized vortex core states.

Findings

The protocol maps the ratio of local charge and probability densities.

Distinctive features of Majorana modes persist despite mode hybridization.

The method offers a clear experimental signature for Majorana vortex modes.

Abstract

The combination of two-dimensional Dirac surface states with s-wave superconductivity is expected to generate localized topological Majorana zero modes in vortex cores. Putative experimental signatures of these modes have been reported for heterostructures of proximitized topological insulators, iron-based superconductors or certain transition metal dichalcogenides. Despite these efforts, the Majorana nature of the observed excitation is still under debate. We propose to identify the presence of Majorana vortex modes using a nonlocal transport measurement protocol originally employed for one-dimensional settings. In the case of an isolated subgap state, the protocol provides a spatial map of the ratio of local charge- and probability-density which offers a clear distinction between Majorana and ordinary fermionic modes. We show that these distinctive features survive in the experimentally relevant case of hybridizing vortex core modes.