Excitonic gap, phase transition, and quantum Hall effect in graphene

TL;DR

This paper proposes that the degeneracy removal in graphene under strong magnetic fields results from a phase transition involving excitonic gap formation, explaining Hall conductivity observations and predicting behavior under various conditions.

Contribution

It introduces a theoretical model linking degeneracy removal to an excitonic gap phase transition in graphene, aligning with experimental Hall conductivity data.

Findings

Reproduces experimental Hall conductivity in graphene

Predicts excitonic gap dependence on temperature and gate voltage

Describes the dynamics of degeneracy removal in strong magnetic fields

Abstract

We suggest that physics underlying the recently observed removal of sublattice and spin degeneracies in graphene in a strong magnetic field describes a phase transition connected with the generation of an excitonic gap. The experimental form of the Hall conductivity is reproduced and the main characteristics of the dynamics are described. Predictions of the behavior of the gap as a function of temperature and a gate voltage are made.