Structure and electronic properties of Au intercalated hexagonal-boron-nitride/graphene bilayer

Based on density functional calculations, we study the structural and electronic properties of Au-intercalated hybrid bilayer composed of a single layer of hexagonal-boron-nitride (h-BN) and a single layer of graphene. Focusing on Au substituted doping in the h-BN layer, we find that the C–C bond length in the lower graphene layer has only minor changes, which implies that the lower graphene layer in the h-BN/graphene bilayer keeps well the original C lattice. Our results show that the Au-doped h-BN/graphene bilayer structure is stable with Au atom tightly confined in a small region between the upper and lower layers, with an estimated energy barrier of about 1.94 eV for the Au dopant to diffuse to the lower graphene layer. Semiconductor to metallic change is found due to the generation of localized mid-states near the Fermi level arising from the hybridization between the occupied states of the Au atom and the B, C and N atoms in the h-BN/graphene hybrid bilayer. Charge transfer occurs from Au dopant to both h-BN layer and graphene layer, increasing the carrier density in the ultra-thin atomic hybrid bilayer.