Probing unconventional superconductivity in proximitized graphene by impurity scattering

TL;DR

This paper shows how impurity scattering can be used to identify the pairing symmetry in proximitized graphene, revealing distinct resonance patterns for different superconducting states and their dependence on doping levels.

Contribution

It introduces a method using impurity-induced resonances to differentiate between various superconducting pairing symmetries in graphene.

Findings

d-wave states exhibit subgap resonances with distinct spatial patterns

s-wave states show no subgap resonances

supergap resonances are linked to the Dirac point and are suppressed at higher doping

Abstract

We demonstrate how potential impurities are a very powerful tool for determining the pairing symmetry in graphene proximity-coupled to a spin-singlet superconductor. All d-wave states are characterized by subgap resonances, with spatial patterns clearly distinguishing between nodal and chiral d-wave symmetry, while s-wave states have no subgap resonances. We also find strong supergap impurity resonances associated with the normal state Dirac point. Sub- and supergap resonances only interact at very low doping levels, then causing suppression of the supergap resonances.