Charge Fluctuations in Geometrically Frustrated Charge Ordering System

Abstract

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 transfer-type molecular conductors and transition metal oxides. Two different lattice structures are considered: (a) one-dimensional chain with intersite Coulomb interaction of nearest neighbor V_1 and that of next-nearest neighbor V_2, and (b) two-dimensional square lattice with V_1 along the squares and V_2 along one of the diagonals. From previous studies, charge ordered insulating states are known to be unstable in the frustrated region, i.e., V_1 \simeq 2V_2 for case (a) and V_1 \simeq V_2 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.

8 pages, 9 figures

References in corpus (13)

• Correlated Electrons in High Temperature Superconductors
• Charge-ordering, commensurability and metallicity in the phase diagram of layered Na(x)CoO(2)
• Charge Ordering in Organic ET Compounds
• Possible effects of charge frustration in Na${}_x$CoO${}_2$: bandwidth suppression, charge orders and resurrected RVB superconductivity
• Large dielectric constant and giant nonlinear conduction in the organic conductor theta-(BEDT-TTF)_2CsZn(SCN)_4
• Quantum Melting of Charge Order due to Frustration in Two-Dimensional Quarter-Filled Systems
• Novel Charge Order and Superconductivity in Two-Dimensional Frustrated Lattice at Quarter Filling
• New aspects of Verway transition in magnetite
• Mean-field study of charge order with long periodicity in $\theta$-(BEDT-TTF)${}_2$X
• Metal-insulator transition and charge ordering in the extended Hubbard model at one-quarter filling
• Effects of Next-Nearest-Neighbor Repulsion on One-Dimensional Quarter-Filled Electron Systems
• Charge Freezing in Zig-zag Chain Cuprates PrBa2Cu4O8 Observed by Cu Nuclear Quadrupole Resonance
• Anomalous behaviors of the charge and spin degrees of freedom in the CuO double chains of PrBa${}_2$Cu${}_4$O${}_8$

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