Monte-Carlo study of the semimetal-insulator phase transition in monolayer graphene with realistic inter-electron interaction potential

TL;DR

This study uses first-principle simulations to analyze the phase transition in monolayer graphene, revealing that realistic electron interactions keep it in a conducting phase, close to a transition point.

Contribution

It provides the first numerical evidence that realistic screened Coulomb interactions prevent spontaneous chiral symmetry breaking in suspended graphene.

Findings

Graphene remains in the conducting phase with unbroken chiral symmetry.

Screened Coulomb potential differs from unscreened models, aligning with experimental data.

Graphene is near a phase transition, indicating potential for symmetry breaking under stronger interactions.

Abstract

We report on the results of the first-principle numerical study of spontaneous breaking of chiral (sublattice) symmetry in suspended monolayer graphene due to electrostatic interaction, which takes into account the screening of Coulomb potential by electrons on $\sigma$-orbitals. In contrast to the results of previous numerical simulations with unscreened potential, we find that suspended graphene is in the conducting phase with unbroken chiral symmetry. This finding is in agreement with recent experimental results by the Manchester group \cite{Elias et al, 2011}. Further, by artificially increasing the interaction strength we demonstrate that suspended graphene is quite close to the phase transition associated with spontaneous chiral symmetry breaking, which suggests that fluctuations of chirality and nonperturbative effects might still be quite important.