Graphene: from materials science to particle physics

TL;DR

This paper reviews the interdisciplinary research on graphene, focusing on its electronic properties, low-temperature conductivity puzzles, and the potential for excitonic gap formation due to strong Coulomb interactions, bridging condensed matter and particle physics.

Contribution

It provides a comprehensive overview of recent progress in understanding graphene's electronic behavior, especially the role of Coulomb interactions and lattice field theory insights.

Findings

Suspended graphene is near the critical coupling for excitonic gap formation.

Lattice field theory suggests strong Coulomb interactions influence conductivity.

Recent experiments show trends consistent with semiconductor-like resistivity at low temperatures.

Abstract

Since its discovery in 2004, graphene, a two-dimensional hexagonal carbon allotrope, has generated great interest and spurred research activity from materials science to particle physics and vice versa. In particular, graphene has been found to exhibit outstanding electronic and mechanical properties, as well as an unusual low-energy spectrum of Dirac quasiparticles giving rise to a fractional quantum Hall effect when freely suspended and immersed in a magnetic field. One of the most intriguing puzzles of graphene involves the low-temperature conductivity at zero density, a central issue in the design of graphene-based nanoelectronic components. While suspended graphene experiments have shown a trend reminiscent of semiconductors, with rising resistivity at low temperatures, most theories predict a constant or even decreasing resistivity. However, lattice field theory calculations have revealed that suspended graphene is at or near the critical coupling for excitonic gap formation due to strong Coulomb interactions, which suggests a simple and straightforward explanation for the experimental data. In this contribution we review the current status of the field with emphasis on the issue of gap formation, and outline recent progress and future points of contact between condensed matter physics and Lattice QCD.