Yu-Shiba-Rusinov states and topological superconductivity in Ising paired superconductors

TL;DR

This paper explores how Ising superconductivity in 2D materials influences Yu-Shiba-Rusinov states and enables topological superconductivity with Majorana fermions due to strong spin-orbit coupling effects.

Contribution

It demonstrates the impact of Ising spin-orbit coupling on YSR states and shows the potential for realizing topological superconductivity in magnetic impurity chains.

Findings

Strong anisotropy in magnetic field response of YSR states

Topological superconductivity can be achieved in impurity chains

Presence of Majorana fermions in the YSR band

Abstract

An unusual form of superconductivity, called Ising superconductivity, has recently been uncovered in mono- and few-layered transition metal dichalcogenides. This 2D superconducting state is characterized by the so-called Ising spin-orbit coupling (SOC), which produces strong oppositely oriented effective Zeeman fields perpendicular to the 2D layer in opposite momentum space valleys. We examine the Yu-Shiba-Rusinov (YSR) bound states localized at magnetic impurities in Ising superconductors and show that the unusual SOC manifests itself in unusually strong anisotropy in magnetic field response of zero bias conductance peaks observable in STM experiments on impurity sites. For a chain of magnetic impurities with moments parallel to the plane of Ising superconductors we show that the low energy YSR band can host topological superconductivity and Majorana fermions as a direct manifestation of Ising spin-orbit coupling induced topological effects.