Semiconducting Electronic Structure of Graphene Adsorbed on Insulating Substrate: Fragility of the Graphene Linear Dispersion Band

Using the first-principle total-energy procedure within the framework of the density functional theory, we study the electronic structure of graphene adsorbed on hexagonal boron nitride (h-BN). We find that the linear dispersion band of graphene is fragile and that graphene adsorbed on h-BN exhibits semiconducting properties with a narrow energy gap. The energy gap size depends weakly on the relative atomic arrangement between graphene and the h-BN substrate. Nonuniform electron density on the substrate causes an imbalance in the electrostatic potential between the two sublattices on graphene, leading to their semiconducting property when adsorbed on h-BN. (C) 2010 The Japan Society of Applied Physics