Abstract
We present an ab initio numerical many-body calculation of the band plot in freestanding graphene. We consider the full ionic and electronic structure introducing 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 single-particle excitations and to the plasmon. The self-energy does not open the band gap.
- Received 28 March 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.226405
©2008 American Physical Society