Quasiparticle properties of graphene antidot lattices

Abstract

A periodic array of holes (antidot lattice) transforms graphene from a semimetal into a semiconductor with a tunable band gap. The magnitude of the gap is highly sensitive to the size and separation of the holes. In the present work, the properties of graphene antidot lattices are analyzed using atomistic models. Density-functional theory (DFT) and tight-binding parameterization of DFT bands usually underestimate band gaps and generally produce incorrect results for other properties related to excited states. To correct this error we consider quasiparticle (QP) corrections to the band structure of graphene antidot lattices within the tight-binding parameterization of the graphene QP band structure of Gr\uneis et al. [Phys. Rev. B 78, 205425 (2008)]. In addition, the optical response is calculated from the QP band structure. We find that band gaps increase by about 15% in the QP model when the hole is small compared to the unit cell. Finally, QP effects on excitons are addressed using the Wannier model with a spatially varying screening.