Incompressible States of Dirac Fermions in Graphene with Anisotropic Interactions

TL;DR

This paper investigates how anisotropic interactions affect the incompressible quantum Hall states of Dirac fermions in graphene, revealing the persistence of these states up to a critical anisotropy and the emergence of new collective excitation branches.

Contribution

It introduces a formalism to incorporate anisotropy in graphene's Dirac fermion system and analyzes its impact on incompressible states and collective excitations.

Findings

Incompressible states survive anisotropy up to a critical value.

Anisotropy creates two branches in collective excitations.

Short-range pair-correlation functions are significantly affected.

Abstract

We report on the properties of incompressible states of Dirac fermions in graphene in the presence of anisotropic interactions and a quantizing magnetic field. We introduce the necessary formalism to incorporate the anisotropy in the system. The incopmpressible state in graphene is found to survive the anisotropy upto a critical value of the anisotropy parameter. The anisotropy also introduces two branches in the collective excitations of the corresponding Laughlin state. It strongly influences the short-range behavior of the pair-correlation functions in the incompressible ground state.