Majorana edge modes of topological exciton condensate with superconductors

TL;DR

This paper explores the emergence of Majorana edge modes in a topological exciton condensate system interfaced with superconductors, proposing a nano-structured setup to realize and detect unpaired Majorana fermions.

Contribution

It introduces a novel system combining topological insulators and superconductors to realize Majorana modes via exciton condensation with a phase shift.

Findings

Counter-propagating Majorana modes appear at the boundary with superconducting phase shift

Proposed nano-structured system can host unpaired Majorana fermions

Experimental signatures for detecting the topological exciton condensate are discussed

Abstract

I study the edge states of the topological exciton condensate formed by Coulomb interaction between two parallel surfaces of a strong topological insulator. When the condensate is contacted by superconductors with a {\pi} phase shift across the two surfaces, a pair of counter-propagating Majorana modes close the gap at the boundary. I propose a nano-structured system of topological insulators and superconductors to realize unpaired Majorana fermions. The Majorana signal can be used to detect the formation of the topological exciton condensate. The relevant experimental signatures as well as implications for related systems are discussed.