Ab initio GW many-body effects in graphene.
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.
Trevisanutto
Paolo E
PE
Institut Néel, CNRS and UJF, Grenoble, France.
Giorgetti
Christine
C
Reining
Lucia
L
Ladisa
Massimo
M
Olevano
Valerio
V