Charge ordering in quarter-filled ladder systems coupled to the lattice

Abstract

We investigate charge ordering in the presence of electron-phonon coupling for quarter-filled ladder systems by using Exact Diagonalization. As an example we consider NaV2O5 using model parameters obtained from first-principles band-structure calculations. The relevant Holstein coupling to the lattice considerably reduces the critical value of the nearest-neighbor Coulomb repulsion at which formation of the zig-zag charge-ordered state occurs, which is then accompanied by a static lattice distortion. Energy and length of a kink-like excitation on the background of the distorted lattice are calculated. Spin and charge spectra on ladders with and without static distortion are obtained, and the charge gap and the effective spin-spin exchange parameter J are extracted. J agrees well with experimental results. Analysis of the dynamical Holstein model, restricted to a small number of phonons, shows that low frequency lattice vibrations increase the charge order, accompanied by dynamically produced zig-zag lattice distortions.

arXiv comment11 pages, 17 figures, revised version as to appear in Phys. Rev. B

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Cited by in corpus (8)

• Optical characterization of platinum-halide ladder compounds
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• Single-particle spectral function of quarter-filled ladder systems
• Photoinduced Structural Phase Transitions in Polyacene
• Creation and destruction of a spin gap in weakly coupled quarter-filled ladders
• Charge order induced by electron-lattice interaction in NaV2O5
• Finite-temperature investigation of quarter filled ladder systems
• Electronic Properties of α'-NaV_2O_5