Surface states characterization in the strongly interacting graphene/Ni(111) system

By combining nonlinear photoemission experiments and density functional theory calculations, we study the modification of Ni(111) surface states induced by the presence of graphene. The main result is that graphene is able to displace the Ni(111) surface states from the valence band close to the Fermi level uncovering the d-band of Ni. The shift of the surface states away from the Fermi level modifies their k-dispersion and the effective mass. The unoccupied image state of graphene/Ni(111) has been also characterized. The ab initio calculations give a theoretical insight into the electronic properties of graphene/Ni(111) in the two stable top-fcc and top-bridge phases showing that the interface properties are poorly dependent on the stacking. The screening properties to an externally applied electric field are also discussed.