Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 42: Transport

HL 42.3: Vortrag

Donnerstag, 15. März 2018, 15:30–15:45, EW 015

Classical magnetoconductivity maximum in two-dimensional Lorentz gases — Jakob Schluck¹, Nima Siboni², Jürgen Horbach², and •Thomas Heinzel¹ — ¹Solid State Physics Laboratory, Heinrich-Heine-Universität Düsseldorf — ²Institute for Theoretical Physics, Heinrich-Heine-Universität Düsseldorf

Two-dimensional Lorentz gases in the classical regime, formed by electrons moving in an array of identical but randomly placed obstacles, show a magnetoconductivity maximum that becomes visible only for high obstacle densities where the mean free path is comparable to the size of the obstacles.[1] It has been predicted by numerical simulations but its origin has remained obscure.[2,3] Here, we show that this maximum is a consequence of superdiffusive electron motion at intermediate time scales. The conductivity maximum turns out to be located at a magnetic field dependent obstacle density which equals the geometric mean of the two phase boundaries of the system.[1] The dependence of this effect on the size and shape of the obstacles is discussed as well. [1]N. H. Siboni et al., preprint arXiv:1708.01039 [cond-mat.dis-nn]. [2]A. Kuzmany and H. Spohn, Phys. Rev. E 57, 5544 (1998). [3]W. Schirmacher et al., Phys. Rev. Lett. 115, 240602 (2015).