Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: Graphene: Electronic Properties, Structure and Substrate Interaction

O 44.2: Poster

Dienstag, 8. März 2016, 18:15–20:30, Poster E

Robust ballistic transport phenomena in epitaxial graphene nanoribbons — •Johannes Aprojanz, Jens Baringhaus, Maren Wehr, Felix Klösel, and Christoph Tegenkamp — Leibniz Universität Hannover, Institut für Festkörperphysik, 30167 Hannover, Germany

Graphene nanoribbons (GNRs) are of particular importance for future carbon-based electronics. Their outstanding electronic properties, especially the presence of topologically protected ballistic transport channels, make them a prime candidate for a new class of fully coherent devices. However, the large amount of defects introduced by conventional lithography processes prevents the formation of such edge channels. The self-assembling growth of GNRs on the sidewalls of SiC mesa structures overcomes this obstacle leading to the observation of exceptional ballistic transport properties. With local transport experiments by means of a 4-tip STM, two fundamentally different ballistic modes can be identified. One is thermally activated and exhibits a mediocre mean free path in the order of several hundred nm, the other is temperature independent and shows an exceptionally long mean free path larger than 10 µm [1]. The roughness of the underlying SiC substrate is identified as a major source for electronic scattering. Consequently, the mean free path is shown to be directly dependent on the width of the substrate terraces [2].
Baringhaus et al., Nature 506, 349 (2014)
Baringhaus et al., APL 106, 043109 (2015)