Experimental and theoretical study of the morphology of commensurate and incommensurate graphene layers on Ni single-crystal surfaces

The paper reports on a scanning tunneling microscopy (STM) study and computer simulation with an N-body interatomic interaction potential of a graphite monolayer (i.e., graphene) on the Ni(111), (110), (755), and (771) single-crystal surfaces. Unlike the case of graphene on Ni(111), which forms a solid single-crystal coating with (1 X 1) structure, graphene on the Ni(110) surface forms a complex crystal structure distorted substantially by interaction with the substrate. Calculations of the graphene/Ni(110) system have revealed that the strong chemical interaction of carbon with nickel gives rise to a noticeable curving of the graphene layer on a scale of a few angstroms. The model thus derived has permitted proper interpretation of the experimental data obtained by STM, as well as prediction of the main result of studies of graphene formed on faceted surfaces, which have revealed the ability of graphene to coat geometrically nonuniform surfaces in the form of a curved continuous film.