Electronic structure and imaging contrast of graphene moiré on metals

• Published in: Scientific reports Vol. 3; no. 1; p. 1072
• Main Authors: Voloshina, E. N., Fertitta, E., Garhofer, A., Mittendorfer, F., Fonin, M., Thissen, A., Dedkov, Yu. S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17-01-2013; Nature Publishing Group
• Subjects: 639/301/119/995; 639/301/357/918/1055; 639/766/119/544; 639/925/918/1052; Adsorption; Humanities and Social Sciences; Metals; Microscopy; multidisciplinary; Quantum dots; Scanning; Science; Short term memory; Spectroscopy; Spectrum analysis; Topography; Transition metals
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep01072

Realization of graphene moiré superstructures on the surface of 4
d
and 5
d
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 moiré supercell, which determine the adsorption sites for molecules or metal clusters on graphene/Ir(111).