Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 7: Graphene I: Structure and Dynamics
O 7.3: Vortrag
Montag, 7. März 2016, 11:00–11:15, H24
Electron interference in ballistic graphene nanoconstrictions — •Johannes Aprojanz1, Jens Baringhaus1, Mikkel Settnes2, Stephen Power2, Anti-Pekka Jauho2, and Christoph Tegenkamp1 — 1Leibniz Universität Hannover, Institut für Festkörperphysik, 30167 Hannover, Germany — 2Technical University of Denmark, DTU Nanotech, Center for Nanostructured Graphene (CNG), 2800 Kgs. Lyngby, Denmark
Graphene nanoconstrictions (GNCs) are a central building block of future carbon electronic devices. However, the synthesis of constrictions with well-defined edges is challenging. Here, we use the tip of a scanning tunneling microscope (STM) for the local etching of graphene, which allows to define GNCs with variable dimensions of down to 1 nm. The GNCs are etched into fully ballistic graphene nanoribbons hosted on the sidewalls of SiC mesa structures [1]. Due to the highly precise etching technique as well as the exceptional electronic quality of the graphene (e.g. mean free path > 10 µm), this system is ideal to study coherent transport phenomena. Therefore, the transport characteristics of constrictions with various dimensions are recorded by means of a variable temperature 4-tip-STM. Electron interference at the abrupt graphene interfaces gives rise to characteristic conductance peaks and transport gaps. Their appearance is described by a tight-binding and recursive Green’s function approach which especially highlights the robustness of the resonances features against temperature as well as disorder.
Baringhaus et al., Nature 506, 349 (2014)