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Finite-temperature phase transitions in quasi-one-dimensional molecular conductors

Research paper by Hitoshi Seo, Yukitoshi Motome, Takeo Kato

Indexed on: 30 Nov '06Published on: 30 Nov '06Published in: Physics - Strongly Correlated Electrons



Abstract

Phase transitions in 1/4-filled quasi-one-dimensional molecular conductors are studied theoretically on the basis of extended Hubbard chains including electron-lattice interactions coupled by interchain Coulomb repulsion. We apply the numerical quantum transfer-matrix method to an effective one-dimensional model, treating the interchain term within mean-field approximation. Finite-temperature properties are investigated for the charge ordering, the "dimer Mott" transition (bond dimerization), and the spin-Peierls transition (bond tetramerization). A coexistent state of charge order and bond dimerization exhibiting dielectricity is predicted in a certain parameter range, even when intrinsic dimerization is absent.