Regensburg 2004 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 30: Postersitzung IV: Kritische Ph
änomene, Quantenstörstellen, niederdimensionale Systeme

TT 30.6: Poster

Donnerstag, 11. März 2004, 14:30–19:00, Poster A

Comparative numerical study of localization in disordered electron systems — •Gerald Schubert¹, Alexander Weiße², and Holger Fehske¹ — ¹Institut für Physik, Ernst-Moritz-Arndt Universität Greifswald, 17487 Greifswald, Germany — ²School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia

Taking into account that a proper description of disordered systems should focus on distribution functions, the authors develop a powerful numerical scheme for the determination of the probability distribution of the local density of states (LDOS), which is based on a Chebyshev expansion with kernel polynomial refinement and allows the study of large finite clusters (up to 100³). As the distribution of the LDOS shows a significant change at the disorder induced delocalization-localization transition, the so-called typical density of states, defined as the geometric mean of the LDOS, emerges as a natural order parameter. Using this method, we calculate the phase diagram for the three dimensional Anderson model, treat correlated disorder in one dimension and consider the quantum percolation problem on a simple cubic lattice.