Related papers: Two-electron bound state formation in the t-J-U mo…
We consider modified $t-J$ model with minimum of single-hole dispersion at the points $(0,\pm \pi)$, $(\pm \pi,0)$. It is shown that two holes on antiferromagnetic background produce a bound state which properties strongly differs from the…
In this work, we continue the study of the supersymmetric t-J model with 1/r^2 hopping and exchange without translational invariance. A set of Jastrow wavefunctions are obtained for the system, with eigenenergies explicitly calculated. The…
Exchange couplings are calculated for Li2VOSiO4 using LDA. While the sum of in-plane couplings J_1 + J_2 = 9.5 \pm 1.5 K and the inter-plane coupling J_{perp} \sim 0.2 - 0.3 K agree with recent experimental data, the ratio J_2/J_1 \sim 12…
We develop strong-coupling series expansion methods to study two-particle spectra of quantum lattice models. At the heart of the method lies the calculation of an effective Hamiltonian in the two-particle subspace. We explicitly consider an…
Pulsed-field magnetization experiments (fields $B$ of up to 85 T and temperatures $T$ down to 0.4 K) are reported on nine organic Cu-based two-dimensional (2D) Heisenberg magnets. All compounds show a low-$T$ magnetization that is concave…
We investigate the phase diagram of the spin-orbit-coupled three orbital Hubbard model at arbitrary filling by means of dynamical mean-field theory combined with continuous-time quantum Monte Carlo. We find that the spin-freezing crossover…
We study a multiple-spin exchange model on a triangular lattice, which is a possible model for low-density solid 3He films. Due to strong competitions between ferromagnetic three-spin exchange and antiferromagnetic four-spin one, the ground…
From calculations of the high temperature series for the free energy of the two-dimensional t-J model we construct series for ratios of the free energy per hole. The ratios can be extrapolated very accurately to low temperatures and used to…
The crossover from two- to three-dimensional critical behavior of nearly antiferromagnetic itinerant electrons is studied in a regime where the inter-plane single-particle motion of electrons is quantum-mechanically incoherent because of…
The boundary of phase separation of the two-dimensional t-J model is investigated by the power-Lanczos method and Maxwell construction. The method is similar to a variational approach and it determines the lower bound of the phase…
The properties of a dilute electron gas, coupled to the lattice degrees of freedom, are studied and compared with the properties of an electron gas at half-filling, where spinless fermions with two orbitals per lattice site are considered.…
The tilt pattern of the CuO_6 octahedra in the LTT phase of the cuprate superconductors leads to planar anisotropies for the exchange coupling and hopping integrals. Here, we show that these anisotropies provide a possible structural…
A key step in unraveling the mysteries of materials exhibiting unconventional superconductivity is to understand the underlying pairing mechanism. While it is widely agreed upon that the pairing glue in many of these systems originates from…
Long-range and anisotropic dipolar interactions profoundly modify the dynamics of particles hopping in a periodic lattice potential. We report the realization of a generalized t-J model with dipolar interactions using a system of ultracold…
In order to clarify possible multipole states of Sm-based filled skutterudite compounds, we investigate multipole susceptibility of a multiorbital Anderson model dynamically coupled with Jahn-Teller phonons by using a numerical…
In Mott insulators with a half-filled $t_{2g}$ shell the Hund's rule coupling induces a spin-3/2 orbital-singlet ground state. The spin-orbit interaction is not expected to qualitatively impact low-energy degrees of freedom in such systems.…
We study the interlayer pairing states in layered systems of two different 2d electronic subsystems, one with relativistic linear and the other with non-relativistic parabolic spectrum. The complex order parameter of the paired state has a…
We describe a class of parity- and time-reversal-invariant topological states of matter which can arise in correlated electron systems in 2+1-dimensions. These states are characterized by particle-like excitations exhibiting exotic braiding…
The normal-state resistivity of the cuprate superconductors is metallic in the $ab$ plane but is characteristic of an insulator along the $c$ direction, leading to the possibility of the remarkable phenomenon of confinement. By continuity,…
A microscopic theory for rare-earth ferromagnetic hexaborides, such as Eu(1-x)Ca(x)B6, is proposed on the basis of the double-exchange Hamiltonian. In these systems, the reduced carrier concentrations place the Fermi level near the mobility…