Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 28: Correlated Electrons: Metal-Insulator Transition 1

TT 28.7: Vortrag

Donnerstag, 28. Februar 2008, 11:15–11:30, H 2053

Static Screening and Delocalization Effects in the Hubbard-Anderson Model — •Peter Henseler¹, Johann Kroha¹, and Boris Shapiro² — ¹Physikalisches Institut, Universität Bonn, Nußallee 12, 53115 Bonn, Germany — ²Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel

We study the suppression of electron localization due to the screening of the disorder potential in a Hubbard-Anderson model within a static picture, where interactions are absorbed into the redefinition of the random on-site energies, leading to an interaction-induced renormalization of the random distribution of onsite energies.

First the one-dimensional case is discussed, where we focus on the change of the electron localization length at the Fermi level. Two different approximations are presented, either one yielding a non-monotonic dependence of the localization length on the interaction strength, with a pronounced maximum at an intermediate interaction strength. We then investigate the higher-dimensional case, applying the selfconsistent theory of Anderson localization to the present problem, and a comparison with recent numerical results is presented.