Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 28: Poster Session: Graphen; Transport properties; Transport in high magnetic fields / Quantum Hall effect; Metal-semiconductor hybrid systems
HL 28.22: Poster
Montag, 11. März 2013, 16:00–20:00, Poster A
Optical conductivity of the Anderson model calculation using Kernel Polynomial Method — •Paul Wenk1, John Schliemann1, and Georges Bouzerar2 — 1Institut I - Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany — 2Institut Néel, 25 avenue des Martyrs, B.P. 166, 38042 Grenoble Cedex 09, France
We investigate the optical conductivity of a three-dimensional system with non-interacting electrons in a random potential (Anderson model) in linear response.[1] The application of the Chebyshev expansion method[2,3] allows for the analysis of large systems at finite temperatures. However, an improper choice of expansion cutoff and Fermi-Energy can lead to unphysical results - not only concerning negative Drude weights. By applying the f-sum rule[4] and a precise analysis of the spectrum degeneracies we resolve the conductivity-artifacts and calculate the suppression of the Drude weight as a function of impurity strength, the Drude weight being the order-parameter for the Metal-Insulator transition.
[1] P. Wenk et al. in prep. (2013)
[2] A. Weiße et al. Rev. Mod. Phys. 78, 275 (2006)
[3] A. Weiße Eur. Phys. J. B 40, 125 (2004)
[4] G. Bouzerar et al. Phys. Rev. B 49, 12 (1994)