https://doi.org/10.1140/epjb/e2005-00117-4
Hund's coupling and the metal-insulator transition in the two-band Hubbard model
1
Institute for Theoretical Physics, University of Göttingen,
Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
2
Center for Electronic Correlations and Magnetism,
Theoretical Physics III, Institute of Physics, University of Augsburg,
86135 Augsburg, Germany
Corresponding author: a pruschke@theorie.physik.uni-goettingen.de
Received:
8
November
2004
Revised:
22
February
2005
Published online:
20
April
2005
The Mott-Hubbard metal-insulator transition is investigated in a two-band Hubbard model within dynamical mean-field theory. To this end, we use a suitable extension of Wilson's numerical renormalization group for the solution of the effective two-band single-impurity Anderson model. This method is non-perturbative and, in particular, allows to take into account the full exchange part of the Hund's rule coupling between the two orbitals. We discuss in detail the influence of the various Coulomb interactions on thermodynamic and dynamic properties, for both the impurity and the lattice model. The exchange part of the Hund's rule coupling turns out to play an important role for the physics of the two-band Hubbard model and for the nature of the Mott-transition.
PACS: 71.10.Fd – Lattice fermion models (Hubbard model, etc.) / 71.27.+a – Strongly correlated electron systems; heavy fermions / 71.30.+h – Metal-insulator transitions and other electronic transitions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005
