Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 28: Correlated Electrons: Metal-Insulator Transition 1

TT 28.9: Vortrag

Donnerstag, 28. Februar 2008, 11:45–12:00, H 2053

Micro-domain formation near the first-order Mott-Hubbard transition — •Qinyong Liu and Johann Kroha — Physikalisches Institut, Universität Bonn, Germany

Near the first order Mott-Hubbard transition of the Hubbard model there is a region where metallic and insulating states can coexist in a finite range of temperatures. We study the formation of insulating or metallic micro-domains embedded in the metallic or insulating phase, respectively, within this coexistence region. In order to calculate the behavior of the density of states across a domain wall, the dynamical mean field theory (DMFT) is generalized to a layer-DMFT, where the selfenergy remains local, but the effective impurity is coupled to different dynamical baths, depending on its distance from the domain wall. We use the non-crossing approximation (NCA) as the impurity solver. Our results allow to compute the free energy of a micro-domain in dependence on its size and, hence, the thermal distribution of domain sizes in depencence of temperature. These results may be relevant for understanding the anomalous temperature dependence of the conductivity near the Mott-Hubbard transition.