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TT: Fachverband Tiefe Temperaturen

TT 101: Transport - Poster Session

TT 101.31: Poster

Donnerstag, 3. April 2014, 15:00–19:00, P2

Ab-initio calculation of local current-flow in functionalized graphene armchair nano-ribbons — •Jan Wilhelm, Michael Walz, and Ferdinand Evers — Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76133 Karlsruhe, Germany and Institut für Theorie der Kondensierten Materie, D-76128 Karlsruhe, Germany

We calculate the local current density in graphene armchair nano-ribbons employing AITRANSS, our DFT-based transport simulation tool. [1,2] The simulations for pristine ribbons indicate that the current flows along streamlines. Neighboring streamlines are separated by stripes of almost vanishing flow. These streamlines form a strongly textured current pattern with gradients that exceed an order of magnitude on the scale of the lattice constant.

Due to the pronounced texture of current flows, the ribbon exhibits a very strong sensitivity to the placing of adsorbates. Backscattering off the adsorbates is strong, if they are located within a streamline and weak, otherwise. We observe that a single adsorbant, e.g., H or OH, when properly placed on the ribbon (width, e.g., 11 carbon atoms) can suppress the current by more than two orders of magnitude.
A. Arnold, F. Weigend, F. Evers, J. Chem. Phys. 126, 174101 (2007)
A. Bagrets, J. Chem. Theory Comput. 9, 2801 (2013)