Related papers: ``Flux'' state in double exchange model
The ground state of the $S=1/2$ $J_{1}-J_{1}$ Heisenberg model on the 2D square lattice with arbitrary signs of exchange constants is considered. States with different spin long-range order types (antiferromagnetic checkerboard, stripe,…
We present density-matrix renormalization group results for the ground state properties of two-leg Hubbard ladders. The half-filled Hubbard ladder is an insulating spin-gapped system, exhibiting a crossover from a spin-liquid to a…
We study the equilibrium spin configuration of the 2D Hubbard model at low doping, when a long-range magnetic order is still present. We use the spin-density-wave formalism and examine the two suggested candidates for a ground state: the…
We present large-scale dynamical simulations of electronic phase separation in the single-band double-exchange model based on deep-learning neural-network potentials trained from small-size exact diagonalization solutions. We uncover an…
The two-dimensional $t$-$J$ model in the ground state is investigated by the power Lanczos method. The pairing-pairing correlation function for $d_{x^2-y^2}$-wave symmetry is enhanced in the realistic parameter regime for high-$T_c$…
Groundstate magnetism of the one-band Hubbard model on the frustrated square lattice where both nearest-neighbour $t_1$ and next-nearest-neighbour $t_2$ hoppings are considered at half-filling are revisited within mean field approximation.…
In a recent paper [Phys. Rev. Lett. 91, 117201 (2003)], it is argued that an itinerant antiferromagnet in an external magnetic field undergoes a spin-flip transition, in marked contrast with the behavior of a localized antiferromagnet: for…
By using variational wave functions and quantum Monte Carlo techniques, we investigate the interplay between electron-electron and electron-phonon interactions in the two-dimensional Hubbard-Holstein model. Here, the ground-state phase…
We construct an effective gauge field theory model describing a 2D quantum antiferromagnet in the flux phase ground state. Due to period doubling the number of gauge fields is four rather than the naively expected single one. These…
Recently an antiferromagnetic metal phase has been proposed in double perovskites materials like Sr$_{2}$FeMoO$_{6}$ (SFMO), when electron doped. This material has been found to change from half-metallic ferromagnet to antiferromagnetic…
We study spin-state transition and phase separation involving this transition based on the milti-orbital Hubbard model. Multiple spin states are realized by changing the energy separation between the two orbitals and the on-site Hund…
We study electronic properties of AA-stacked graphene bilayers. In the single-particle approximation such a system has one electron band and one hole band crossing the Fermi level. If the bilayer is undoped, the Fermi surfaces of these…
We study a possibility of a non-homogeneous magnetic order (cryptoferromagnetic state) in heterostructures consisting of a bulk superconductor and a ferromagnetic thin layer that can be due to the influence of the superconductor. The…
We study an exchange coupled system of itinerant electrons and localized fermion pairs resulting in a resonant pairing formation. This system inherently contains resonating fermion pairs on bonds which lead to a superconducting phase…
We study intersubband spin density collective modes in double-layer quantum Hall systems at $\nu=2$ within the time-dependent Hartree-Fock approximation. We find that these intersubband spin density excitations may soften under…
Spin-wave resonance measurements were performed in the mixed magnetic phase regime of a Pd-doped FeRh epilayer that appears as the first-order ferromagnetic-antiferromagnetic phase transition takes place. It is seen that the measured value…
In the framework of the two-band model of a doped semiconductor the self-consistent equations describing the transition into the excitonic insulator state are obtained for the 2D case. It is found that due to the exciton-electron…
The two-dimensional Kondo lattice model with both nearest and next-nearest neighbor exchange interactions is studied within a mean-field approach and its phase diagram is determined. In particular, we allow for lattice translation symmetry…
Independently exchange biased subsystems can coexist in FeF2/Ni bilayers after various field-cooling protocols. We find double hysteresis loops for intermediate cooling fields, while for small or large cooling fields a negatively or…
Exchange bias is often observed when anti-ferromagnetic and ferromagnetic phases coexist. The coexistence of two competing magnetic phases can persist to the lowest temperatures if the disorder-broadened 1st order transition separating them…