Dynamical properties of a strongly correlated model for quarter-filled layered organic molecular crystals

Abstract

The dynamical properties of an extended Hubbard model, which is relevant to quarter-filled layered organic molecular crystals, are analyzed. We have computed the dynamical charge correlation function, spectral density, and optical conductivity using Lanczos diagonalization and large-N techniques. As the ratio of the nearest-neighbour Coulomb repulsion, V, to the hopping integral, t, increases there is a transition from a metallic phase to a charge ordered phase. Dynamical properties close to the ordering transition are found to differ from the ones expected in a conventional metal. Large-N calculations display an enhancement of spectral weight at low frequencies as the system is driven closer to the charge ordering transition in agreement with Lanczos calculations. As V is increased the charge correlation function displays a plasmon-like mode which, for wavevectors close to (pi,pi), increases in amplitude and softens as the charge ordering transition is approached. We propose that inelastic X-ray scattering be used to detect this mode. Large-N calculations predict superconductivity with dxy symmetry close to the ordering transition. We find that this is consistent with Lanczos diagonalization calculations, on lattices of 20 sites, which find that the binding energy of two holes becomes negative close to the charge ordering transition.

22 pages, 16 eps figures; caption of Fig. 5 corrected

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Cited by in corpus (32)

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• Quantum Melting of Charge Order due to Frustration in Two-Dimensional Quarter-Filled Systems
• Possible charge instabilities in two-dimensional doped Mott insulators
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• Melting of charge order in the low-temperature state of an electronic ferroelectric
• One-electron self energies and spectral functions for the t-J model in the large-N limit
• Unconventional metallic conduction in two-dimensional Hubbard-Wigner lattices
• Strong particle-hole asymmetry of charge instabilities in doped Mott insulators
• Cooperative effect of phonons and electronic correlations for superconductivity in cobaltates
• Collective excitation of a short-range charge ordering in $\theta$-$\mbox{(BEDT-TTF)}_2\mbox{CsZn(SCN)}_4$
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• Charge-Density-Excitation Spectrum in the t-t'-J-V Model
• Electron-phonon interaction dressed by electronic correlations near charge ordering as the origin for superconductivity in cobaltates
• Electron self-energy from quantum charge fluctuations in the layered t-J model with long-range Coulomb interaction
• The metal-insulator transition in the organic conductor ${\beta }^{\prime \prime }$-(BEDT-TTF)${}_2$Hg(SCN)${}_2$Cl
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• Role of dynamical non-double-occupancy excitations on the quasiparticle damping of the $t-J$ model in the large-$N$ limit
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• Charge-sensitive vibrational modes in the (EDT-TTF-OX)_2AsF_6 chiral molecular conductors
• Signatures of electron-electron correlations in the optical spectra of $\alpha$-(BEDT-TTF)${}_{2}M$Hg(SCN)${}_4$ ($M$=NH${}_4$ and Rb)
• Beyond on-site Hubbard interaction in charge dynamics of cuprate superconductors
• Theoretical perspectives on charge dynamics in high-temperature cuprate superconductors