Creating Majorana modes from segmented Fermi surface

TL;DR

This paper proposes a new platform for creating Majorana bound states using 2D gapless superconducting states in spin-helical systems, enabling robust topological channels with practical advantages.

Contribution

It introduces a novel method to generate Majorana modes from segmented Fermi surfaces in 2D superconductors with minimal tuning and enhanced stability.

Findings

Topological 1D channels formed via quantum confinement

Realizable with magnetic insulators on topological insulators

Large topological gaps achievable

Abstract

We present a new platform for creating Majorana bound states from 2D gapless superconducting state in spin-helical systems under the in-plane Zeeman field. Topological 1D channels are formed by quantum confinement of quasiparticles via Andreev reflection from the surrounding fully gapped superconducting region. Our proposal can be realized using narrow strips of magnetic insulators on top of proximitized 3D topological insulators. This setup has key advantages that include: small Zeeman fields, no required fine-tuning of chemical potential, removal of the low-energy detrimental states, and large attainable topological gap.