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HL: Fachverband Halbleiterphysik

HL 15: Graphene: Structure and Theory I

HL 15.3: Vortrag

Montag, 26. März 2012, 15:30–15:45, EW 201

Atomic structure and spectroscopy of graphene edges on Ir(111) — •Soo-hyon Phark¹, Jérôme Borme^1,2, 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.