Regensburg 2016 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 27: Poster - Statistical Physics, Critical Phenomena, Brownian motion
DY 27.5: Poster
Dienstag, 8. März 2016, 18:15–21:00, Poster C
Behavior of electronic states on random Voronoi-Delaunay lattices in the orthogonal and the unitary universality class — •Martin Puschmann1, Philipp Cain1, Michael Schreiber1, and Thomas Vojta2 — 1Institute of Physics, Technische Universität Chemnitz, Chemnitz, Germany — 2Department of Physics, Missouri University of Science and Technology, Rolla, Missouri, USA
The random Voronoi-Delaunay lattice (VDL) is defined as a set of bonds between randomly positioned sites. The bonds connect neighboring Voronoi cells and are obtained by the Delaunay triangulation. The resulting topologically disordered lattice features strong anticorrelations between the coordination numbers of neighboring sites. The disorder fluctuations therefore decay qualitatively faster with increasing length scale than those of generic random systems. A recent study showed that this modifies the Harris and Imry-Ma criteria and leads to qualitatively changes of the scaling behavior at magnetic phase transitions [1]. We consider the transport of non-interacting electrons on two- and three dimensional random VDLs without and with magnetic fields. The electronic wave functions are analyzed by multifractal analysis. Without magnetic fields, we obtain results in accordance to the orthogonal universality class [2]. Applying magnetic fields introduces a phase shift to the local wave function. This shift is proportional to the area of the local Delaunay triangle. We show how the topological aspect affects the behavior of the wave functions in magnetic VDLs and whether this is compatible with unitary universality class.
[1] PRL 113, 120602 (2014) [2] EPJ B 88, 314 (2015)