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

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® (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.