Related papers: Coexistence of distinct charge fluctuations in $\t…
Charge ordering (CO) with long-periodicities in a geometrically frustrated system, theta-(BEDT-TTF)2X, is numerically studied. We consider interacting fermion models on the anisotropic triangular lattice: the extended Hubbard model and the…
Motivated by the various physical properties observed in $\theta$-(BEDT-TTF)$_2$X, we study the ground state of extended Hubbard model on two-dimensional anisotropic triangular lattice at 1/4-filling with variational Monte Carlo method. It…
We present a scenario for the peculiar coexistence of charge fluctuations observed in quasi-2D 1/4-filled organic conductors $\theta$-(BEDT-TTF)$_2X$ in the quantum critical regime where the charge ordering is suppressed down to zero…
We study the charge ordering (CO) in the one-dimensional (1D) extended Hubbard model at quarter filling where the nearest-neighbor Coulomb repulsion and dimerization in the hopping parameters are included. Using the cluster mean-field…
The extended Hubbard model in the atomic limit, which is equivalent to lattice $S=1/2$ fermionic gas, is considered on the triangular lattice. The model includes onsite Hubbard $U$ interaction and both nearest-neighbor ($W_{1}$) and…
Triangular-lattice systems attract a lot of attention due to various frustration-induced and strongly correlated effects. Here, we focus on the charge-ordering phenomenon by means of investigation of the extended Hubbard model with…
A simple effective model of charge ordered insulators is studied. The tight binding Hamiltonian consists of the effective on-site interaction U and the intersite density-density interactions Wij (both: nearest-neighbour and…
We consider the extended Hubbard model on a two-dimensional square lattice at half-filling. The model is investigated using the strong coupling diagram technique. We sum infinite series of ladder diagrams allowing for full-scale charge and…
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…
Charge ordering phenomenon in $\theta$-(BEDT-TTF)$_2$X is studied by using 1/4-filled extended Hubbard model on an anisotropic triangular lattice through mean-field approximation. It is found that a metallic charge ordered state with…
We study a one-dimensional extended Hubbard model with longer-range Coulomb interactions at quarter-filling in the strong coupling limit. We find two different charge-ordered (CO) ground states as the strength of the longer range…
The charge ordering phenomena in quasi two-dimensional 1/4-filled organic compounds (ET)_2X (ET=BEDT-TTF) are investigated theoretically for the $\theta$ and $\alpha$-type structures, based on the Hartree approximation for the extended…
We investigate ground state properties of a quasi-one-dimensional electron-lattice coupled model for quarter-filled molecular conductors. The effective one-dimensional extended Hubbard model coupled to adiabatic lattice degree of freedom is…
We investigate the ground-state phase diagram of the one-dimensional "ionic" Hubbard model with an alternating periodic potential at half-filling by numerical diagonalization of finite systems with the Lanczos and density matrix…
We study the Holstein-Hubbard model at half filling to explore the ordered phases such as the charge density wave and antiferromagnet. The Coulomb interaction is rewritten in terms of auxiliary fields. By treating the auxiliary fields and…
Effects of geometrical frustration in low-dimensional charge ordering systems are theoretically studied, mainly focusing on dynamical properties. We treat extended Hubbard models at quarter-filling, where the frustration arises from…
We investigate the phase diagram of a quarter filled Hubbard ladder with nearest-neighbor Coulomb repulsion using bosonization and renormalization group approach. Focusing on the strong-repulsion regime, we discuss the effect of an…
Lattice effects on photo-excited states in interacting charge frustrated system are examined. Real time dynamics in the interacting spinless fermion model on a triangular lattice coupled to lattice vibration are analyzed by applying the…
We study the ground state of the one-dimensional half-filled Hubbard model with on-site (nearest-neighbor) repulsive interaction $U$ ($V$) and nearest-neighbor hopping $t$. In order to obtain an accurate phase diagram, we consider various…
We study the electronic states of the anisotropic triangular lattice Hubbard model at half filling, which is a simple effective model for the organic superconducting $\kappa$-BEDT-TTF compounds. We treat the effect of the Coulomb…