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Slave-boson mean-field theory of the Mott transition in the two-band Hubbard model

Rüegg, A. ; Indergand, M. ; Pilgram, S. ; Sigrist, M.

In: The European Physical Journal B - Condensed Matter and Complex Systems, 2005, vol. 48, no. 1, p. 55-64

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    Titre
    • Slave-boson mean-field theory of the Mott transition in the two-band Hubbard model
    Auteur
    • Rüegg, A.. ETH Hönggerberg, 8093, Zürich, Switzerland
    • Indergand, M.. ETH Hönggerberg, 8093, Zürich, Switzerland
    • Pilgram, S.. ETH Hönggerberg, 8093, Zürich, Switzerland
    • Sigrist, M.. ETH Hönggerberg, 8093, Zürich, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • The European Physical Journal B - Condensed Matter and Complex Systems, 2005, vol. 48, no. 1, p. 55-64. EDP Sciences
    Autre version électronique
    Classification
    • Physique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:312514
    Summary
    Abstract.: We apply the slave-boson approach of Kotliar and Ruckenstein to the two-band Hubbard model with an Ising like Hund's rule coupling and bands of different widths. On the mean-field level of this approach we investigate the Mott transition and observe both separate and joint transitions of the two bands depending on the choice of the inter- and intra-orbital Coulomb interaction parameters. The mean-field calculations allow for a simple physical interpretation and can confirm several aspects of previous work. Beside the case of two individually half-filled bands we also examine what happens if the original metallic bands possess fractional filling either due to finite doping or due to a crystal field which relatively shifts the atomic energy levels of the two orbitals. For appropriate values of the interaction and of the crystal field we can observe a band insulating state and a ferromagnetic metal