Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 36: Posters: Bio/organic Molecules on Surfaces, Graphene, Solid/liquid interfaces, Metal Substrates, Electronic Structure Theory
O 36.40: Poster
Dienstag, 1. April 2014, 18:30–22:00, P1
Transport properties of epitaxially grown graphene nanoribbons — •Jens Baringhaus1, Frederik Edler1, Christian Seidel1, Claire Berger2, Walter A. de Heer2, and Christoph Tegenkamp1 — 1Leibniz Universität Hannover, Institut für Festkörperphysik, 30167 Hannover, Germany — 2Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
For graphene nanoribbons with zig-zag type edges the existence of topologically protected electronic edge states is theoretically predicted. Hence, exceptional transport phenomena such as ballistic transport with a mean free path in the µm range become accessible. The experimental realization of such nanoribbons requires a gentle patterning avoiding any damaging of the edges. For this purpose, we use a selective graphitization process on SiC mesa structures which allows the direct growth of graphene nanoribbons without post-processing. The electronic properties of the ribbons are investigated with scanning tunneling spectroscopy. A local density of states typical for a zig-zag type edge is observed, revealing features corresponding to the two topologically protected zeroth subbands. The transport properties of the ribbons are further analyzed by means of a 4-tip STM system. Extremely robust ballistic transport with a mean free path up to 10 µm is observed for temperatures up to room temperature. Transport in just one or both zeroth subbands can be detected depending on the probe spacing. Transport data of around 50 different ribbons are analyzed statistically, showing the reliability and reproducibility of the observed phenomena.