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E. Voloshina, E. Fertitta, A. Garhofer, F. Mittendorfer, M. Fonin, A. Thissen, Y. Dedkov:
"Electronic structure and imaging contrast of graphene moiré on metals";
Scientific Reports, 3 (2013), 10721 - 10727.

Realization of graphene moire´ superstructures on the surface of 4d and 5d transition metals offers templates
with periodically modulated electron density, which is responsible for a number of fascinating effects,
including the formation of quantum dots and the site selective adsorption of organic molecules or metal
clusters on graphene. Here, applying the combination of scanning probe microscopy/spectroscopy and the
density functional theory calculations, we gain a profound insight into the electronic and topographic
contributions to the imaging contrast of the epitaxial graphene/Ir(111) system. We show directly that in
STM imaging the electronic contribution is prevailing compared to the topographic one. In the force
microscopy and spectroscopy experiments we observe a variation of the interaction strength between the tip
and high-symmetry places within the graphene moire´ supercell, which determine the adsorption sites for
molecules or metal clusters on graphene/Ir(111).