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arXiv · cond-mat/9512005

Lattice-gas model for alkali-metal fullerides: body-centered-cubic structure

Gyorgy Szabo·Laszlo Udvardi
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Abstract

A Coulomb lattice-gas model with a host lattice screening mechanism is adapted to describe the ordering phenomena in alkali-metal fullerides of body-centered-cubic structure. It is assumed that the electric charge of an alkali ion residing at a tetrahedral interstitial site is completely screened by its first-neighbor C$_{60}$ molecules. The electronic energy of the C$_{60}^{x-}$ ion is also taken into consideration as a charged spherical shell. By means of these assumptions an effective (short range) pair interaction is obtained between two alkali ions. The resultant lattice-gas model is analyzed by using two- and six-sublattice mean-field approximations. The thermodynamic properties are summarized in phase diagrams for different shell radii.

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Gyorgy Szabo, Laszlo Udvardi. 1995-12-01. Lattice-gas model for alkali-metal fullerides: body-centered-cubic structure. https://doi.org/10.1088/0953-8984%2F10%2F19%2F009

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