Importance of on-site interaction in graphene

Abstract

We use the Gutzwiller method to investigate the importance of the on-site Coulomb interaction in graphene. We apply it to Hubbard Hamiltonian to study the renormalization of the kinetic energy in graphene due to the on-site Coulomb interaction. We find that a reasonable strength of the interaction has a very weak effect in reducing the kinetic energy. Hence we predict that the Brinkmann-Rice metal-insulator transition in graphene is not possible. The effect is understood in terms of the high kinetic energy in graphene.