Coulomb interaction and semimetal-insulator transition in graphene

TL;DR

This paper investigates how strong Coulomb interactions can induce a transition from a semimetal to an insulator in graphene by generating an excitonic gap, analyzing thermodynamic properties across phases.

Contribution

It provides a theoretical calculation of specific heat and susceptibility changes during the semimetal-insulator transition driven by Coulomb interactions in graphene.

Findings

Distinct behaviors of specific heat in different phases

Susceptibility varies significantly across the transition

Identification of a critical interaction strength 

Abstract

The strong Coulomb interaction between massless Dirac fermions can drive a semimetal-insulator transition in single-layer graphene by dynamically generating an excitonic fermion gap. There is a critical interaction strength $\lambda_c$ that separates the semimetal phase from the insulator phase. We calculate the specific heat and susceptibility of the system and show that they exhibit distinct behaviors in the semimetal and insulator phases.