Topological superconductivity and Majorana fermions in half-metal / superconductor heterostructure

TL;DR

This paper demonstrates that interface spin-orbit coupling can induce topological superconductivity with Majorana fermions in half-metal/superconductor heterostructures, challenging previous assumptions about their proximity effects.

Contribution

It introduces a mechanism for inducing $p_x + ip_y$ superconductivity in half-metals via interface spin-orbit coupling, enabling topological phases with Majorana modes.

Findings

Induced topological superconductivity in half-metals with interface SOC

Identification of VTe and CrO2 as suitable single-band half-metal candidates

Estimate of the bulk energy gap for the induced topological state

Abstract

As a half-metal is spin-polarized at its Fermi level by definition, it was conventionally thought to have little proximity effect to an s-wave superconductor. Here we show that, with interface spin-orbit coupling, $p_x +ip_y$ superconductivity without spin degeneracy is induced on the half-metal, and we give an estimate of its bulk energy gap. Therefore a single-band half-metal can give us a topological superconductor with a single chiral Majorana edge state. Our band calculation shows that two atomic layers of VTe or CrO$_2$ is a single-band half-metal for a wide range ($\sim$0.1eV) of Fermi energy and thus is a suitable candidate material.