Related papers: Spectral-weight function of the ionic Hubbard mode…
The single particle spectral-weight function (SWF) of the ionic Hubbard model at half filling is calculated in the cluster perturbation theory approximation. An abrupt change of regime in the low-energy region, near the chemical potential,…
We study the one-band Hubbard model at half filling with hopping asymmetry and its effective model at finite but large U up to the second order of tmix/U. Two variational wave functions, the resonating valence bond (RVB) wave function and…
The ionic Hubbard model on a cubic lattice is investigated using analytical approximations and Wilson's renormalization group for the charge excitation spectrum. Near the Mott insulating regime, where the Hubbard repulsion starts to…
We investigate the phases of the ionic Hubbard model in a two-dimensional square lattice using determinant quantum Monte Carlo (DQMC). At half-filling, when the interaction strength or the staggered potential dominate we find Mott and band…
The ionic Hubbard model is investigated at half filling at zero temperature. We apply the cellular dynamical mean-field theory to the one-dimensional ionic Hubbard model to compute local quantities such as double occupancy and staggered…
A repulsive Hubbard model with both spin-asymmetric hopping (${t_\uparrow\neq t_\downarrow}$) and a staggered potential (of strength $\Delta$) is studied in one dimension. The model is a compound of the mass-imbalanced (${t_\uparrow\neq…
We employ the dynamical mean field approximation to study the effects of ionic potential ($\Delta$) on the square lattice Hubbard model. At half-filling when the staggered potential ($\Delta$) dominates the on-site Hubbard interaction…
The singular value decomposition technique is used to reconstruct the electronic spectral weight function for a half-filled Hubbard model with on-site repulsion $U=4t$ from Quantum Monte Carlo data. A two-band structure for the…
Using grand canonical Quantum Monte Carlo (QMC) simulations combined with Maximum Entropy analytic continuation, as well as analytical methods, we examine the one- and two-particle dynamical properties of the Hubbard model on two coupled…
Using Quantum Monte Carlo we compute thermodynamics and spectra for the orbitally degenerate Hubbard model in infinite spatial dimensions. With increasing orbital degeneracy we find in the one-particle spectra: broader Hubbard bands…
In this paper we study the dominant microscopic processes that generate nearly the whole one-electron removal and addition spectral weight of the one-dimensional Hubbard model for all values of the on-site repulsion $U$. We find that for…
A detailed study of electronic phase transitions in the ionic Hubbard model at half filling is presented. Within the dynamical mean field approximation a series of transitions from the band insulator via a metallic state to a Mott-Hubbard…
We investigate the infinite-dimensional two-orbital Hubbard model at arbitrary band fillings. By means of the self-energy functional approach, we discuss the stability of the metallic state in the systems with same and different bandwidths.…
We investigate the metal insulator transitions at finite temperature for the Hubbard model with diagonal alloy disorder. We solve the dynamical mean field theory equations with the non crossing approximation and we use the coherent…
We calculate the one-electron spectral function of the attractive-U Hubbard model in two dimensions. We work in the intermediate coupling and low density regime and evaluate analytically the self-energy. The results are obtained in a…
The mechanism that drives a metal-insulator transition in an undoped quasi-one-dimensional Mott insulator is examined in the framework of the Hubbard model with two different hoppings t_{perp 1} and t_{perp 2} between nearest-neighbor…
We report the emergence or broadening of exotic magnetic metallic phases upon explicit breaking of $SU(2)$ symmetry by introduction of mass imbalance in a variant of Hubbard model, known as the ionic Hubbard model in the presence of…
Dynamic properties of the three-dimensional single-band Hubbard model are studied using Quantum Monte Carlo combined with the maximum entropy technique. At half-filling, there is a clear gap in the density of states and well-defined…
We study the transitions from band insulator to metal to Mott insulator in the ionic Hubbard model on a two dimensional square lattice using determinant Quantum Monte Carlo. Evaluation of the temperature dependence of the conductivity…
Using the Ogata-Shiba wave function, the spectral functions of the one-dimensional infinite U Hubbard model are calculated for various concentrations. It is shown that the ``shadow band'' feature due to 2k_F fluctuations becomes more…