Flat band superconductivity in strained Dirac materials

TL;DR

This paper explores how strain-induced flat bands in 2D Dirac materials like graphene can significantly enhance superconductivity, leading to higher critical temperatures and unique electronic properties.

Contribution

It introduces a model showing strain-induced flat bands cause increased critical temperature and inhomogeneous order parameters in superconducting Dirac materials.

Findings

Higher critical temperature in strained flat band systems

Inhomogeneous order parameter with two-peak local density of states

Large, uniform, and isotropic supercurrent despite inhomogeneity

Abstract

We consider superconducting properties of a two-dimensional Dirac material such as graphene under strain that produces a flat band spectrum in the normal state. We show that in the superconducting state, such a model results in a highly increased critical temperature compared to the case without the strain, inhomogenous order parameter with two-peak shaped local density of states and yet a large and almost uniform and isotropic supercurrent. This model could be realized in strained graphene or ultracold atom systems and could be responsible for unusually strong superconductivity observed in some graphite interfaces and certain IV-VI semiconductor heterostructures.