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Sensitivity of the Mott Transition to Non-cubic Splitting of the Orbital Degeneracy: Application to NH3 K3C60

Nicola Manini·Giuseppe E. Santoro·Andrea Dal Corso·Erio Tosatti
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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 Δof the degeneracy. The phase diagram in the U-Δplane 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 Δ<< 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 NH3 K3C60 is discussed.

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Nicola Manini, Giuseppe E. Santoro, Andrea Dal Corso, Erio Tosatti. 2002-03-22. Sensitivity of the Mott Transition to Non-cubic Splitting of the Orbital Degeneracy: Application to NH3 K3C60. https://doi.org/10.1103/physrevb.66.115107

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