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DY: Fachverband Dynamik und Statistische Physik
DY 10: Posters I
DY 10.27: Poster
Monday, March 14, 2011, 17:00–19:00, P4
Anomalous magnetoresistance in a 2D Lorentz-Gas — •Benedikt Fuchs1, Teresa Bauer1, Felix Höfling2, and Thomas Franosch3 — 1ASC and CeNS, Fakultät für Physik, Ludwig-Maximilians-Universität München, Germany — 2Max-Planck-Institut für Metallforschung, Stuttgart, and Institut für Theoretische und Angewandte Physik, Universität Stuttgart, Germany — 3Institut für Theoretische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
We simulate the transport of electrons through a two-dimensional random array of obstacles under the influence of a perpendicular magnetic field. At low density, a percolation transition arises, at which transport sets in. It can be rationalized as follows: For fixed magnetic field, the electrons circle around few obstacles and stay near their starting point at very low density, while they proceed from one obstacle to the next at intermediate density, traversing the whole system for sufficiently dense obstacles. This transition and the dependence of the critical density on the magnetic field have been anticipated before [1], but have yet never been verified in a simulation. We examplify the transition at several points, corrobating the predicted behavior. Anomalous transport is observed at these points for more than six orders of magnitude in time by both power-law behaviour of the MSD and power-law decay of the diffusion coefficient.
[1] A. Kuzmany and H. Spohn, Phys. Rev. E 57(5), 5544 (1998)