# Classifying superconductivity in Moir\'e graphene superlattices

## TL;DR

This study investigates the pairing symmetry of superconductivity in twisted bilayer graphene Moiré superlattices, finding evidence for s-wave and specific p-wave symmetries through analysis of critical fields and currents.

## Contribution

It introduces a detailed analysis of pairing symmetries in Moiré graphene superlattices using critical field and current measurements, highlighting the likely dominance of s-wave and certain p-wave symmetries.

## Key findings

- s-wave and specific p-wave symmetries are likely dominant
- Superconducting parameters suggest possible two-band superconductivity
- Further data needed to conclusively distinguish pairing symmetries

## Abstract

Several research groups have reported on the observation of superconductivity in bilayer graphene structures where single atomic layers of graphene are stacked and then twisted at angles $\theta$ forming Moir\'e superlattices. The characterization of the superconducting state in these 2D materials is an ongoing task. Here we investigate the pairing symmetry of bilayer graphene Moir\'e superlattices twisted at $\theta$ = 1.05{\deg}, 1.10{\deg} and 1.16{\deg} for carrier doping states varied in the range of n=0.5-1.5 10^(12) cm^(-2) (where superconductivity can be realized) by analyzing the temperature dependence of the upper critical field Bc2(T) and the self-field critical current Jc(sf,T) within currently available models for single- and two-band s-, d-, p- and d+id-wave gap symmetries. Extracted superconducting parameters show that only s-wave and a specific kind of p-wave symmetries are likely to be dominant in bilayer graphene Moir\'e superlattices. More experimental data is required to distinguish between the s- and remaining p-wave symmetries as well as the suspected two-band superconductivity in these 2D superlattices.

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Source: https://tomesphere.com/paper/1902.07410