Andrés Greco

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

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-neighbor 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 collective mode which, for wave vectors 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 d(xy) 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.

Electronic properties of correlated metals in the vicinity of a charge-order transition : Optical spectroscopy of α -(BEDT, -TTF ))2MHg( SCNn )4 (M=NH4, Rb, TI)

The infrared spectra of the quasi-two-dimensional organic conductors

Non-Fermi Liquid Behavior in Nearly Charge Ordered Layered Metals

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Possible charge instabilities in two-dimensional doped Mott insulators

-(BEDT-TTF)

Size-Shape Relationships in the Mesozoic Planispiral Ammonites

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Large-n expansion based on the Hubbard operator path integral representation and its application to the t-J model

M

Large- N expansion based on the Hubbard operator path integral representation and its application to the t − J model. II. The case for finite J

Hg(SCN)

Evidence for two competing order parameters in underdoped cuprate superconductors from a model analysis of Fermi-Arc effects.

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Short-ranged and short-lived charge-density-wave order and pseudogap features in underdoped cuprate superconductors

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