Novel Mott transitions in a nonisotropic two-band Hubbard model.
The Mott transition in a two-band Hubbard model involving subbands of different widths is studied as a function of temperature using dynamical mean field theory combined with exact diagonalization. The phase diagram is shown to exhibit two successive first-order transitions if the full Hund's rule coupling is included. In the absence of spin-flip and pair-exchange terms the lower transition remains first-order while the upper becomes continuous.
Liebsch
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Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany. a.liebsch@fz-juelich.de