Work

Classifying superconductivity in Moiré graphene superlattices

Year: 2020

Type: article

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 θ forming Moiré superlattices. The characterization of the superconducting state in these 2D materials is an ongoing task. Here we investigate the pairing symmetry of bilayer graphene Moiré superlattices twisted at θ = 1.05°, 1.10° and 1.16° for carrier doping states varied in the range of n = (0.5 − 1.5) · 1012 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 – all of which start from phonon-mediated BCS theory – 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 Moiré 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.

Source: Scientific Reports

DOI: 10.1038/s41598-019-57055-w

Authors: E. F. Talantsev, R. C. Mataira, W. P. Crump