Within dynamical mean-field theory, we study the metal-insulator transition of a twofold orbitally degenerate Hubbard model as a function of a splitting Delta of the degeneracy. The phase diagram in the U-Delta plane exhibits two-band and one-band metals, as well as the Mott insulator. The correlated two-band metal is easily driven to the insulator state by a strikingly weak splitting Delta<W of the order of the Kondo-peak width zW, where z<1 is the metal quasiparticle weight. The possible relevance of this result to the insulator-metal transition in the orthorhombic expanded fulleride NH3K3C60 is discussed.

Sensitivity of the Mott transition to noncubic splitting of the orbital degeneracy : application to NH3K3C60 / N. Manini, G. Santoro, A. Dal Corso, E. Tosatti. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 66:11(2002), pp. 115107.115107.1-115107.115107.7.

Sensitivity of the Mott transition to noncubic splitting of the orbital degeneracy : application to NH3K3C60

N. Manini;
2002

Abstract

Within dynamical mean-field theory, we study the metal-insulator transition of a twofold orbitally degenerate Hubbard model as a function of a splitting Delta of the degeneracy. The phase diagram in the U-Delta plane exhibits two-band and one-band metals, as well as the Mott insulator. The correlated two-band metal is easily driven to the insulator state by a strikingly weak splitting Delta
Settore FIS/03 - Fisica della Materia
2002
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/205222
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