Graphene Moire’ structures on Ni(001): atomic-scale investigation

Carnevali1, Z. Zou2,3, L. Patera3,4, M. Jugovac3,5, G. Soldano6, C. Africh3, G. Comelli1, M. Mariscal6 and M. Peressi1

1.Department of Physics, University of Trieste, Italy

2.International Center for Theoretical Physics, Italy

3.CNR-IOM Trieste, Italy

4.presently at: Faculty of Physics, University of Regensburg, Germany

5.presently at: Forschungszentrum Jülich, Peter Grünberg Institut, Germany

6.National University of Córdoba, Department of Mathematics and Physics, Argentina

Graphene on Ni(100) forms a variety of Moire’ patterns which can be well explained in atomistic models by the mismatch with the substrate, with periodicity depending on the relative angle between the hexagonal graphene and the square surface lattices. Evidence of the different Moire’ structures is given by high resolution scanning tunneling microscopy images, that are well reproduced by ab-initio simulations. Beyond providing the detailed atomic-scale structures, the numerical simulations allow a deep local characterization of the chemical bonding between the graphene layer and the support. We also discuss the possible formation beneath the graphene of a surface-confined nickel-carbide in specific regions of the Moire’, whose presence is suggested by experimental STM images.