Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 6: Graphene: Electronic properties, structure and substrate interaction I (joint session O/TT)

O 6.1: Vortrag

Montag, 12. März 2018, 10:30–10:45, MA 043

A Molecular Model System for 5-7 Defects in Graphene — •Benedikt P. Klein¹, Markus Franke², Claudio K. Krug¹, Stefan R. Kachel¹, Phil Rosenow¹, Francois Posseik², Martin Schmid¹, Reinhard J. Maurer³, Ralf Tonner¹, Christian Kumpf², and J. Michael Gottfried¹ — ¹Fachbereich Chemie, Philipps-Universität Marburg, Germany — ²Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, Germany — ³Department of Chemistry, University of Warwick, United Kingdom

The electronic and mechanical properties of graphene are strongly influenced by the presence of defects. One important type of defect is the 5-7 motif with a 5-membered ring adjacent to a 7-membered ring. Little is known about the interaction of 5-7 defects with an underlying substrate. In this study, we have obtained insight into this interaction by using molecular model systems. As a model for the 5-7 defects we use azulene, which is a bicyclic aromatic compound with a 5- and a 7-membered ring, while naphthalene is used as a model for the regular 6-6 motif. We investigated both molecules on Cu(111) and Ag(111) using PES, NEXAFS, TPD, scanning probe and NIXSW experiments. To deepen the understanding of the occurring interactions between molecule and surface, periodic DFT calculations were performed. The more localized frontier orbitals of azulene result in a much stronger and more localized interaction with the Cu(111) surface. This leads to interfacial charge transfer in the former LUMO and substantial in-plane and out-of-plane deformations, as well as a much smaller adsorption height.