Regensburg 2004 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 24: Postersitzung III: Korrelierte Elektronen, ”Orbital Physics”
TT 24.17: Poster
Mittwoch, 10. März 2004, 14:30–19:00, Poster A
Charge Fluctuations in the t-U-V1-V2 Model — •Satoshi Ejima1, Florian Gebhard1, Satoshi Nishimoto1, and Yukinori Ohta2 — 1Fachbereich Physik, Philipps-Universität Marburg, 35032 Marburg — 2Department of Physics, Chiba University, Chiba 263-8522, Japan
Recently, charge dynamics has attracted much interest in the transition-metal oxide PrBa2Cu3O7 and in the organic conductor (TYMTSF)2. In the low-energy physics of these materials, charge fluctuations play a crucial role, due to the frustration of the long-range Coulomb interactions.
The minimal model for these systems is the one-dimensional quarter-filled Hubbard model with nearest-neighbor (V1) and next-nearest-neighbor (V2) Coulomb interactions. We investigate the ground state and some excited states using the (dynamical) density-matrix renormalization group technique. We present an accurate phase diagram and discuss the possible emergence of a metallic (or superconducting) phase induced by charge fluctuations. Moreover, we compare our single-chain results with calculations for double-chain systems such as PrBa2Cu4O8 [1].
[1] S. Nishimoto and Y. Ohta, cond-mat/0305610