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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons - Poster Session

TT 20.66: Poster

Wednesday, March 28, 2007, 14:00–17:45, Poster A

Numerical calculation of Wegner estimates for the three-dimensional Bernoulli-Anderson model — •Peter Karmann and Michael Schreiber — Institut für Physik, Technische Universität Chemnitz, 09107 Chemnitz

The Bernoulli-Anderson model is defined as a tight-binding Hamiltonian of non-interacting electrons with a probability distribution of the on-site energies given by a dichotomic or binary measure µ= pδ₀+(1−p)δ_W. We study characteristic features of the density of states using various methods for the numerical diagonalization of sparse matrices. In particular, we determine an upper bound of the probability of finding an eigenvalue near a fixed energy for different system sizes and disorder strengths W. Especially for strong disorder, we give a Wegner estimate for resonances which can be identified with finite-size clusters.