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Updated: Jul 24, 2026

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Metal-insulator transitions: influence of lattice structure, jahn-teller effect, and Hund's rule coupling
Han1, Koch, Gunnarsson
1Max-Planck-Institut fur Festkorperforschung, D-70506 Stuttgart, Germany.
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 A(n)C60 (A = K,Rb). The difference in the lattice structure favors A3C60 (fcc) being a metal and A4C60 (bct) being an insulator, and the coupling to H(g) Jahn-Teller phonons favors A4C60 being nonmagnetic. The coupling to H(g) ( A(g)) phonons decreases (increases) the value U(c) 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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