Straining the Identity of Majorana Fermions

TL;DR

This paper proposes an interferometer setup to detect Majorana fermions on topological insulator-superconductor-ferromagnet junctions, showing how dislocations influence conductance oscillations and reveal Majorana states.

Contribution

It introduces a novel experimental approach using dislocations in topological materials to identify Majorana fermions through conductance measurements.

Findings

Zero temperature magneto-conductance oscillates with different periods depending on dislocation presence.

Dislocations induce asymmetry in conductance as a function of electron energy.

Resonances occur at the coupling energy of Majorana states.

Abstract

We propose an experimental setup of an interferometer for the observation of neutral Majorana fermions on topological insulator - superconductor - ferromagnet junctions. We show that the extended lattice defects naturally present in materials, dislocations, induce spin currents on the edges while keeping the bulk time-reversal symmetry intact. We propose a simple two terminal conductance measurement in an interferometer formed by two edge point contacts, which reveals the nature of Majorana states through the effect of dislocations. The zero temperature magneto-conductance changes from even oscillations with period phi/2 (phi is the flux quantum hc/e) to odd oscillations with period phi, when non-trivial dislocations are present and the Majorana states are sufficiently strongly coupled. Additionally, the conductance acquires a notable asymmetry as a function of the incident electron energy, due to the topological influence of the dislocations, while resonances appear at the coupling energy of Majorana states.