Comment on "Dirac cones reshaped by interaction effects in suspended graphene" by Elias et al., Nature Physics 7, 701 (2011)

TL;DR

This paper discusses different theoretical perspectives on graphene's low-energy behavior, contrasting large N_F semimetal models with small N_F semiconductor predictions, and supports the latter based on recent experimental evidence.

Contribution

It provides a critical analysis of existing models for graphene's electronic properties, emphasizing the relevance of small N_F predictions supported by recent experiments.

Findings

Graphene likely behaves as a narrow gap semiconductor at low energies.

Experimental evidence supports the small N_F model over the large N_F semimetal model.

Theoretical predictions align with recent experimental observations on graphene and graphite.

Abstract

Two different points of view are available to understand the behavior of graphene at low energies. One is considering a large $N_F$ that makes graphene a semimetal, and another for small $N_F < 2.5$ that would make graphene a narrow gap semiconductor (D. T. Son, Phys. rev. B 75, 235423 (2007)), a prediction supported independently by Monte Carlo simulations (J. E. Drut and T. A. L\"ahde, Phys. Rev. Lett. 102, 026802 (2009), see also Phys. Rev. B 79, 241405(R) (2009)). Taking into account recently obtained experimental evidence for weakly coupled graphene layers, i.e. graphite (N. Garc\'ia et al., arXiv/1106.0437), we tend to support the last one.