Effects of electron-electron interactions in suspended graphene

Abstract

We investigate the problem of dynamical gap generation in suspended graphene by long-range Coulomb interactions at strong coupling with Dyson-Schwinger equations. Including renormalization effects on the Fermi velocity we obtain a critical coupling constant $\alpha_c=2.85$ which is larger than the bare coupling $\alpha_0=2.19$ of suspended graphene. This suggests that at low energies the running of the Fermi velocity prevents the emergence of a gapped phase. Our calculation is thus in agreement with the experimental observation that suspended graphene remains in the semimetal phase.