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TT: Fachverband Tiefe Temperaturen
TT 71: Graphene - Preparation and Characterization 2 (jointly with DS, HL, MA, and O)
TT 71.6: Vortrag
Freitag, 15. März 2013, 11:45–12:00, H17
Understanding of the imaging contrast in STM/NC-AFM of graphene on metals — •Elena Voloshina1, Edoardo Fertitta1, Andreas Garhofer2, Florian Mittendorfer2, Mikhail Fonin3, Torben Haenke4, Oliver Schaff4, Thorsten Kampen4, Andreas Thissen4, and Yuriy Dedkov4 — 1Physikalische und Theoretische Chemie, Freie Universität Berlin, 14195 Berlin, Germany — 2Institute of Applied Physics, Vienna University of Technology, Gusshausstr. 25/134, 1040 Vienna, Austria — 3Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany — 4SPECS Surface Nano Analysis GmbH, Voltastraße 5, 13355 Berlin, Germany
Realization of graphene moiré superstructures on the surfaces 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 moiré supercell, which determine the adsorption sites for molecules or metal clusters on graphene/Ir(111).