Model of an exotic chiral superconducting phase in a graphene bilayer

TL;DR

This paper predicts a novel gapless chiral superconducting phase in bilayer graphene characterized by interlayer pairing, exhibiting unconventional thermodynamic properties and drawing analogies to exotic states in nuclear and quark matter.

Contribution

It introduces a new theoretical model of interlayer chiral superconductivity in bilayer graphene with unique thermodynamic behavior and novel pairing symmetry.

Findings

Prediction of a gapless s-wave spin-triplet condensate

Temperature-induced increase in pairing gap

Higher entropy in the superconducting state compared to the normal state

Abstract

We theoretically demonstrate the formation of a new type of unconventional superconductivity in graphene materials, which exhibits gapless property. The studied superconductivity is based on an interlayer pairing of chiral electrons in bilayer graphene, which results in an exotic s-wave spin-triplet condensate order with anomalous thermodynamic properties. These include the possibility of a temperature induced condensation causing an increase of the pairing gap with increasing temperature, and an entropy of the stable superconducting state which can be higher than its value in the normal state. Our study reveals the analogy of the interlayer superconductivity in graphene materials to the color superconductivity in dense quark matter and the gapless pairing states in nuclear matter and ultra-cold atomic gases.