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Metal-insulator transitions: Influence of lattice structure, Jahn-Teller effect, and Hund's rule coupling

J. E. Han·E. Koch·O. Gunnarsson
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Abstract

We study the influence of the lattice structure, the Jahn-Teller effect and the Hund's rule coupling on a metal-insulator transition in AnC60 (A= K, Rb). The difference in lattice structure favors A3C60 (fcc) being a metal and A4C60 (bct) being an insulator, and the coupling to Hg Jahn-Teller phonons favors A4C60 being nonmagnetic. The coupling to Hg (Ag) phonons decreases (increases) the value Uc of the Coulomb integral at which the metal-insulator transition occurs. There is an important partial cancellation between the Jahn-Teller effect and the Hund's rule coupling.

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J. E. Han, E. Koch, O. Gunnarsson. 1999-10-21. Metal-insulator transitions: Influence of lattice structure, Jahn-Teller effect, and Hund's rule coupling. https://doi.org/10.1103/physrevlett.84.1276

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