First-principles study of the structural and electronic properties of graphene absorbed on MnO(111) surfaces

In this work, adsorption of graphene on polar MnO(1 1 1) surface with and without hydrogen coverage was investigated by density functional theory. Local atomic reconstructions of the graphene/H:MnO(1 1 1) interface and their thermodynamic and electronic properties were analyzed for different adsorption models. Bond length and adsorption energy were found for different reconstructions of surface atomic structure in the graphene/H:MnO(1 1 1) systems. Effect of graphene adsorption on the electronic spectrum of the graphene/H:MnO(1 1 1) interface was also studied. The effective charge of carbon atoms and nearest-neighbor atoms were determined for the considered adsorption models. Our calculations show that the charge transfer from carbon atom to nearest-neighbor atoms is due to reconstruction of the local atomic and electronic structures, correlating with the interface hydrogenation concentration. At the interface hydrogen concentration of Θ = 1.0 ML (monolayer), the p–n junction was observed in the graphene and a new state, n-type semiconductor, is qualitatively emerged.