Energetics and electronic structure of graphene adsorbed on HfO2(111): Density functional theory calculations

We report total-energy electronic-structure calculations based on density functional theory performed on graphene adsorbed on the (111) surface of hafnium dioxide (HfO2). We find that the graphene is bound to the HfO2 surface with an interlayer spacing of 3.05 angstrom with a binding energy of about -110 meV per C atom. The electronic structure of the HfO2-adsorbed graphene originates primarily from that of the graphene near the Fermi level. However, a detailed analysis of the electronic structure shows that the linear bands on the Dirac cone are slightly split because of the interaction between the graphene and the HfO2 substrate. The physical origin of this splitting is the hybridization between the p states of the graphene and the O 2p state with Hf d character.