Related papers: Two-hole dynamics in spin ladders
We study the entanglement spectrum of spin-1/2 XXZ ladders both analytically and numerically. Our analytical approach is based on perturbation theory starting either from the limit of strong rung coupling, or from the opposite case of…
The spin-fermion model was previously successful to describe the complex phase diagrams of colossal magnetoresistive manganites and iron-based superconductors. In recent years, two-dimensional magnets have rapidly raised up as a new…
A model of CuO$_2$ planes of cuprate perovskites, containing $d_{x^2-y^2}$ copper orbitals and symmetric combinations of oxygen $p_\sigma$ orbitals, is investigated using the strong coupling diagram technique. This approach allows one to…
We develop a variational formalism in order to study the structure of low energy spectra of frustrated quantum spin systems. It is first applied to trial wavefunctions of ladders with one spin-1/2 on each site. We determine energy minima of…
A two-leg spin-1/2 ladder with diagonal interactions is investigated numerically. We focus our attention on the possibility of columnar dimer phase, which was recently predicted based on a reformulated bosonization theory. By using density…
Exact Diagonalization calculations are presented for the t-J model in the presence of a uniform magnetic field. Results for 2xL ladders (L=8,10,12) and 4x4 square clusters with 1 and 2 holes indicate that the diamagnetic response to a…
We examine the effect of spin gap on single-hole spectral function in the one-dimensional t-J-J'model. At J'/J=1/2, where a dimer state is the ground state, an analytic expression is derived for J/t \to 0. At finite values of J/t, the…
Using the description in terms of the Hubbard operators hole and spin Green's functions of the two-dimensional t-J model are calculated in an approximation which retains the rotation symmetry of the spin susceptibility in the paramagnetic…
Different models for doping of two-orbital chains with mobile $S=1/2$ fermions and strong, ferromagnetic (FM) Hund's rule couplings stabilizing the S=1 spins are investigated by density matrix renormalization group (DMRG) methods. The…
Using a rotationally invariant version of the slave-boson approach in spin space we analyze the stability of stripe phases with large unit cells in the two-dimensional Hubbard model. This approach allows one to treat strong electron…
We propose and analyze a physical system that naturally admits two-dimensional topological nearly flat bands. Our approach utilizes an array of three-level dipoles (effective S = 1 spins) driven by inhomogeneous electromagnetic fields. The…
Doping of a two-orbital chain with mobile S=1/2 Fermions and strong Hund's rule couplings stabilizing the S=1 spins strongly depends on the presence of a level difference among these orbitals. By DMRG methods we find a finite spin gap upon…
The question of spin-charge separation in two-dimensional lattices has been addressed by numerical simulations of the motion of one hole in a half-filled band. The calculations have been performed on finite clusters with Hubbard and t-J…
Schwinger bosons allow for an advantageous representation of quantum double-exchange. We review this subject, comment on previous results, and address the transition to the semiclassical limit. We derive an effective fermionic Hamiltonian…
We perform a systematic investigation of an asymmetric zig-zag spin ladder with inter-leg exchange $J_1$ and different exchange integrals $J_2 \pm \delta$ on both legs. In the weak limit of frustration, the spin model can be mapped to a…
Spin-charge separation is a hallmark of one-dimensional fermionic systems, yet its realization in higher dimensions remains an open question. To address this issue, we investigate a two-leg t-J ladder using the density matrix…
We investigate the ground-state properties of correlated three-leg ladders near 1/3 filling. We apply the density-matrix renormalization group method to the three-leg t-J ladder with strong interchain couplings and evaluate its pairing…
In this work, we study N-leg Kondo ladders at half-filling through the density matrix renormalization group. We found non-zero spin and charge gaps for any finite number of legs and Kondo coupling $J>0$. We also show evidence of the…
It is known that a two-dimensional spin system can acquire a topological Hopf term by coupling to massless Dirac fermions whose energy spectrum has a single cone. But it is challenging to realize the Hopf term in condensed matter physics…
We perform the numerical equivalent of a phase sensitive experiment on doped $t-J$ ladders. We apply proximity effect fields with different complex phases at both ends of an open system and we study the transport of Cooper pairs. Measuring…