Superconductivity of electron-hole pairs in a bilayer graphene system in a quantizing magnetic field

TL;DR

This paper investigates the emergence of a superfluid state of electron-hole pairs in bilayer graphene under a magnetic field, highlighting conditions for phase coherence and potential advantages over traditional materials.

Contribution

It demonstrates the conditions for interlayer phase coherence in graphene bilayers and analyzes the superfluid transition, critical currents, and the benefits of graphene over GaAs heterostructures.

Findings

Interlayer phase coherence occurs with certain Landau level imbalance.

Transition temperature and maximum interlayer distance are determined.

Graphene offers advantages for bilayer electron-hole superconductivity.

Abstract

The state with a spontaneous interlayer phase coherence in a graphene based bilayer quantum Hall system is studied. This state can be considered as a gas of superfluid electron-hole pairs with the components of the pair belonging to different layers. Superfluid flux of such pairs is equivalent to two electrical supercurrents in the layers. It is shown that the state with the interlayer phase coherence emerges in the graphene system if a certain imbalance of the Landau level filling factors of the layers is created. We obtain the temperature of transition into the superfluid state, the maximum interlayer distance at which the phase coherence is possible, and the critical values of the supercurrent. The advantages of use of graphene systems instead of GaAs heterostructures for the realization of the bilayer electron-hole superconductivity is discussed.