Effects of electron-lattice coupling on charge order in θ-(ET) 2X

Yasuhiro Tanaka, Kenji Yonemitsu

研究成果: Article

24 被引用数 (Scopus)

抄録

Charge ordering accompanied by lattice distortion in quasi-two dimensional organic conductors θ-(ET) 2X (ET = BEDT-TTF) is studied by using an extended Hubbard model with Peierls-type electron-lattice couplings within the Hartree-Fock approximation. It is found that the horizontal-stripe charge-ordered state, which is experimentally observed in θ-(ET) 2RbZn(SCN) 4, is stabilized by the self-consistently determined lattice distortion. Furthermore, in the presence of the anisotropy in nearest-neighbor Coulomb interactions V ij, the horizontal charge order becomes more stable than any other charge patterns such as diagonal, vertical and 3-fold-type states. At finite temperatures, we compare the free energies of various charge-ordered states and find a first-order transition from a metallic state with 3-fold charge order to the insulating state with the horizontal charge order. The role of lattice degrees of freedom in the realization of the horizontal charge order and the relevance to experiments on θ-(ET) 2X are discussed.

本文言語English
論文番号053708
ジャーナルjournal of the physical society of japan
76
5
DOI
出版ステータスPublished - 2007 5 1
外部発表はい

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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