Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 26: Metal-Insulator Transition

TT 26.8: Vortrag

Donnerstag, 29. März 2007, 16:00–16:15, H19

Orbitally selective Mott transition in the two-band Hubbard model — •Theodoulos Costi and Ansgar Liebsch — Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich

The two-band Hubbard model with inequivalent bands exhibits as a function of increasing local Coulomb repulsion two, in general quite different, ”Mott” transitions at Coulomb interactions U_c1 and U_c2 respectively. We use the numerical renormalization group and exact diagonalization methods to investigate the nature of the second ”Mott” transition in detail, for isotropic and anisotropic Hund’s exchange [1]. The numerical renormalization group approach uses an effective low energy model which is valid for Coulomb interactions U>U_c1. We show that this model exhibits non-Fermi liquid and bad metallic behavior in the orbitally selective Mott phases for isotropic and anisotropic Hund’s exchange coupling, respectively.

[1] A. Liebsch and T. A. Costi, Eur. Phys. J. B51, 523 (2006)