Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 15: Graphene: Structure and Theory I
HL 15.3: Talk
Monday, March 26, 2012, 15:30–15:45, EW 201
Atomic structure and spectroscopy of graphene edges on Ir(111) — •Soo-hyon Phark1, Jérôme Borme1,2, Augusto León Vanegas1, Marco Corbetta1, Dirk Sander1, and Jürgen Kirschner1 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany — 2International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, 4715-310 Braga, Portugal
We performed scanning tunneling microscopy/spectroscopy (STM/S) on monolayer graphene islands grown on Ir(111). The graphene islands show moiré patterns, which are induced by the lattice mismatch between graphene and Ir(111). The atomic structure at the edge of a graphene depends on the stacking configurations of the edge atoms. The edges of graphene islands terminate with a zigzag carbon configuration and show periodic kinks in the regions of the on-top stacking carbon rings. The periodicity is given by the moiré pattern of the graphene island. The termination of a graphene island at an Ir(111) step also leads to the formation of periodic kinks, of which the positions depend on the orientation of the step edge. We tentatively ascribe these observations to a strong electronic interaction, arising from the broken σ-bond of graphene, between carbon edge atoms and the Ir lattice. Spatially resolved tunnel spectroscopy indicates a considerably reduced density of states at the edges as compared to center regions of the islands.