Topological Larkin-Ovchinnikov phase and Majorana zero mode chain in bilayer superconducting topological insulator films

TL;DR

This paper theoretically demonstrates that bilayer superconducting topological insulator films can host a topologically non-trivial Larkin-Ovchinnikov phase under an in-plane magnetic field, resulting in a Majorana zero mode chain along the edge.

Contribution

It introduces a new topological phase in bilayer superconducting topological insulators driven by magnetic fields, revealing Majorana modes in this system.

Findings

LO phase is topologically non-trivial with Z2 invariant

Majorana zero modes form a chain along the edge

In-plane magnetic field induces the phase transition

Abstract

We theoretically study bilayer superconducting topological insulator film, in which superconductivity exists for both top and bottom surface states. We show that an in-plane magnetic field can drive the system into Larkin-Ovchinnikov (LO) phase, where electrons are paired with finite momenta. The LO phase is topologically non-trivial and characterized by a Z 2 topological invariant, leading to a Majorana zero mode chain along the edge perpendicular to in-plane magnetic fields.