2006/07/31 by Hitoshi Seo, Kenji Tsutsui, Kenji Tsutui +2 · 1 citation
Materials Science · Physics and Astronomy · #Magnetism in coordination complexes #Organic and Molecular Conductors Research #Physics of Superconductivity and Magnetism #cond-mat.str-el
paper · pdf · doi:10.1143/jpsj.75.114707
published as J. Phys Soc. Jpn. 11, 114707 (2006) · 8 pages, 9 figures
arxiv created 2006/07/31 · openalex publication_date 2006/11/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Effects of geometrical frustration in low-dimensional charge ordering systems are theoretically studied, mainly focusing on dynamical properties. We treat extended Hubbard models at quarter-filling, where the frustration arises from competing charge ordered patterns favored by different intersite Coulomb interactions, which are effective models for various charge transfertype molecular conductors and transition metal oxides. Two different lattice structures are considered: (a) one-dimensional chain with intersite Coulomb interaction of nearest neighbor V1 and that of next-nearest neighbor V2, and (b) two-dimensional square lattice with V1 along the squares and V2 along one of the diagonals. From previous studies, charge ordered insulating states are known to be unstable in the frustrated region, i.e., V1 2V2 for case (a) and V1 V2 for case (b), resulting in a robust metallic phase even when the interaction strenghs are strong. By applying the Lanczos exact diagonalization to finite-size clusters, we have found that fluctuations of different charge order patterns exist in the frustration-induced metallic phase, showing up as characteristic low energy modes in dynamical correlation functions. Comparison of such features between the two models are discussed, whose difference will be ascribed to the dimensionality effect. We also point out incommensurate correlation in the charge sector due to the frustration, found in one-dimensional clusters.