A Model Study of the Low-Energy Charge Dynamics of NaV_2O_5

Abstract

An exact-diagonalization technique on small clusters is used to calculate the dynamical density correlation functions of the dimerized t-J chain and coupled anisotropic t-J ladders (trellis lattice) at quarter filling, i.e., the systems regarded as a network of pairs (dimers or rungs) of sites coupled weakly via the hopping and exchange interactions. We thereby demonstrate that the intersite Coulomb repulsions between the pairs induce a low-energy collective mode in the charge excitations of the systems where the internal charge degrees of freedom of the pairs play an essential role. Implications to the electronic states of NaV_2O_5, i.e., fluctuations of the valence state of V ions and phase transition as a charge ordering, are discussed.

4 pages, 4 gif figures. Hardcopies of figures (or the entire manuscript) can be obtained by e-mail request to [email protected]

References in corpus (8)

• NaV_2O_5 as a quarter-filled ladder compound
• Charged Magnons in NaV2O5
• Raman, infrared and optical spectra of the spin-Peierls compound NaV_2O_5
• Anomalous thermal conductivity of NaV2O5 as compared to conventional spin-Peierls system CuGeO3
• Interference of a first-order transition with the formation of a spin-Peierls state in alpha'-NaV2O5?
• NaV_2O_5 as an Anisotropic t-J Ladder at Quarter Filling
• Optical Conductivity of the Trellis-Lattice t-J Model: Charge Fluctuations in NaV_2O_5
• Critical Dimerization Strength of the Quarter-Filled t-J Model

Cited by in corpus (8)

• Thermodynamics of Spin S = 1/2 Antiferromagnetic Uniform and Alternating-Exchange Heisenberg Chains
• Charge Order Driven spin-Peierls Transition in NaV2O5
• One-dimensional dynamics of the d-electrons in ${\alpha }^{\prime }$-NaV${}_2$O${}_5$
• Unconventional anisotropic superexchange in NaV2O5
• Studies of the t-J two-leg ladder via series expansions
• Charge excitations in NaV${}_2$O${}_5$
• Optical conductivity in the CuO double chains of PrBa_2Cu_4O_8: Consequences of charge fluctuation
• Spin and charge excitations in the anisotropic Hubbard ladder at quarter filling with charge-ordering instability