title: Ab initio GW many-body effects in graphene.
abstract: We present an ab initio numerical many-body GW calculation of the band plot in freestanding graphene. We consider the full ionic and electronic structure introducing e-e interaction and correlation effects via a self-energy containing non-Hermitian and dynamical terms. With respect to the density-functional theory local-density approximation, the Fermi velocity is renormalized with an increase of 17%, in better agreement with the experiment. Close to the Dirac point the linear dispersion is modified by the presence of a kink, as observed by angle-resolved photoemission spectroscopy. We demonstrate that the kink is due to low-energy pi-->pi* single-particle excitations and to the pi plasmon. The GW self-energy does not open the band gap.
authors.affiliation: Institut Néel, CNRS and UJF, Grenoble, France.
authors.forename: Paolo E
authors.initials: PE
authors.lastname: Trevisanutto
authors.forename: Christine
authors.initials: C
authors.lastname: Giorgetti
authors.forename: Lucia
authors.initials: L
authors.lastname: Reining
authors.forename: Massimo
authors.initials: M
authors.lastname: Ladisa
authors.forename: Valerio
authors.initials: V
authors.lastname: Olevano