Berlin 2015 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 56: Poster - Statistical Physics

DY 56.23: Poster

Donnerstag, 19. März 2015, 16:00–18:00, Poster A

Multifractal analysis of states in Voronoi-Delaunay lattices — •Martin Puschmann, Philipp Cain, and Michael Schreiber — Institute of Physics, Technische Universität Chemnitz, Chemnitz

The Voronoi-Delaunay lattice (VDL) is a set of nearest-neighbor connections between randomly positioned sites. It is a simple model for amorphous solids and foams. We consider the transport of non-interacting electrons in this lattice and assume that all connections have the same strength. Consequently, the VDL is topologically disordered by connectivity only. Whether this form of disorder is sufficient to obtain localized states in two- and three-dimensional lattices was studied by the multifractal analysis of electronic wave functions and the finite-size scaling approach. We observe localized states in both dimensionalities with energies very close to the band edges. A localization-delocalization transition was found only in the three-dimensional lattice, in accordance with the localization theory. The corresponding critical exponent of localization is equal to the exponent of the orthogonal Wigner-Dyson class. Furthermore, we analyzed the case of additional random on-site potentials in the three-dimensional lattice. We obtain a phase diagram by varying the disorder strength of these potentials. The mixing of these different disorders does not affect the critical exponent.