Related papers: Current-current correlations in the three-band mod…
The interplay between non-trivial band topology and strong electronic correlations is a central challenge in modern condensed matter physics. We investigate this competition on a two-leg ladder model with a p-wave-like hybridisation between…
The strength and effect of Coulomb correlations in the (superconducting when hydrated) x~1/3 and ``enhanced'' x~2/3 regimes of Na(x)CoO2 are evaluated using the correlated band theory LDA+U method. Our results, neglecting quantum…
We study the electronic band-structure and transport properties of a CuO2-plane within the three-band Hubbard model. The Dynamical Mean-Field Theory (DMFT) is used to solve the many particle problem. The calculations show that the optical…
Doped Hubbard model is a simple model for the high-Tc cuprate superconductors, while its ground state remains a challenge. Here, by performing state-of-the-art variational Monte Carlo calculations for the strong-coupling Hubbard model, we…
The role of Coulomb correlations in the iron pnictide LaFeAsO is studied by generalizing exact diagonalization dynamical mean field theory to five orbitals. For rotationally invariant Hund's rule coupling a continuous transition from a…
We discuss duality relations in correlated electronic ladder systems to clarify mutual relations between various conventional and unconventional phases. For the generalized two-leg Hubbard ladder, we find two exact duality relations, and…
The frequency structure of the superconducting correlations in cuprates gives insights on the pairing mechanism. Here we present an exhaustive study of this problem in the two-dimensional Hubbard model with cellular dynamical mean-field…
A model for high temperature superconductors based on the idea of Cooper pairs comprised of electrons from different bands is studied. We propose that the two bands relevant for the cuprates are comprised of Cu dx2-y2, dz2, planar O psigma,…
Here we report results of a density-matrix-renormalization-group (DMRG) calculation of the charge, spin, and pairing properties of a two-leg CuO Hubbard ladder. The outer oxygen atoms as well as the rung and leg oxygen atoms are included…
We study extended Hubbard model on a triangular lattice near doping $x=1/3$, which may be relevant for the recently discovered superconductor Na$_x$CoO$_2 \cdot y$H$_2$O. By generalizing this model to $N$ fermionic species, we formulate a…
Charge ordering is often found in the phase diagram of unconventional superconductors in close proximity to the superconducting state. This has led to the suggestion that fluctuations of charge order can mediate superconducting pairing.…
Extensive numerical studies have demonstrated that the two-dimensional single-band Hubbard model contains much of the key physics in cuprate high-temperature superconductors. However, there is no definitive proof that the Hubbard model…
A self-doping effect between outer and inner CuO$_2$ planes (OPs and IPs) in multi-layer cuprate superconductors is studied. When one considers a three-layer tight-binding model of the Hg-based three-layer cuprate derived from the first…
Recently we presented a new band structure for La(2-x)Sr(x)CuO(4) and other high temperature superconductors in which a second narrow band was seen to cross the primary band at the Fermi level. The existence of this second Fermi level band…
We study the phase diagram of the one-dimensional Hubbard model with next-nearest-neighbor hopping using exact diagonalization, the density-matrix renormalization group, the Edwards variational ansatz, and an adaptation of weak-coupling…
The four-site DCA method of including intersite correlations in the dynamical mean field theory is used to investigate the metal-insulator transition in the Hubbard model. At half filling a gap-opening transition is found to occur as the…
Short-range charge-density wave correlations are ubiquitous in underdoped cuprates. They are largely confined to the copper-oxygen planes and typically oscillate out of phase from one unit cell to the next in the c-direction. Recently, it…
The dynamics of holon-doublon pairs is studied in Hubbard two-leg ladders using the time-dependent Density Matrix Renormalization Group method. We find that the geometry of the two-leg ladder, that is qualitatively different from a…
We present an efficient diagrammatic method to describe nonlocal correlation effects in lattice fermion Hubbard-like models, which is based on a change of variables in the Grassmann path integrals. The new fermions are dual to the original…
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…