相关论文: Instability of antiferromagnetic magnons in strong…
We find evidence for decaying magnons at strong magnetic field in the square lattice spin-1/2 Heisenberg antiferromagnet. The results are obtained using Quantum Monte Carlo simulations combined with a Bayesian inference technique to obtain…
Spin dynamics of the square lattice Heisenberg antiferromagnet, \BaMnGeO, is studied by a combination of bulk measurements, neutron diffraction, and inelastic neutron scattering techniques. Easy plane type antiferromagnetic order is…
Instability of the excitation spectrum of an ordered noncollinear Heisenberg antiferromagnet (AF) with respect to spontaneous two-magnon decays is investigated. We use a spin-1/2 AF on a triangular lattice as an example and examine the…
We study the field dependence of the antiferromagnetic spin-1/2 Heisenberg model on the square lattice by means of exact diagonalizations. In a first part, we calculate the spin-wave velocity, the spin-stiffness, and the magnetic…
We discuss spin-$\frac12$ two-dimensional (2D) Heisenberg antiferromagnet (AF) on a square lattice at T=0 in strong magnetic field H near its saturation value $H_c$. A perturbation approach is proposed to obtain spectrum of magnons with…
We find and characterize the instabilities of the repulsive Hubbard chain in a magnetic field by studing all response functions at low frequency \omega and arbitrary momentum. The instabilities occur at momenta which are simple combinations…
We discuss theoretically static and dynamical properties of $XY$ and Heisenberg antiferromagnets on triangular lattice with random vacancies and substitutional spins. It is shown that the distortion of $120^\circ$ magnetic order produced by…
Dynamical properties of the square-lattice Heisenberg antiferromagnet in applied magnetic field are studied for arbitrary value S of the spin. Above the threshold field for two-particle decays, the standard spin-wave theory yields singular…
We study the stability of some strongly frustrated antiferromagnetic spin lattices in high magnetic fields against lattice distortions. In particular, we consider a spin-s anisotropic Heisenberg antiferromagnet on the square-kagom\'{e} and…
We study high-field magnon dynamics and examine the dynamical structure factor in the quasi-2D tetragonal Heisenberg antiferromagnet with interlayer coupling corresponding to realistic materials. Within spin-wave theory, we show that a…
We analyze instabilities of the collinear up-up-down state of a two-dimensional quantum spin-S spatially anisotropic triangular lattice antiferromagnet in a magnetic field. We find, within large-S approximation, that near the end point of…
We study a classical double exchange magnet with direct antiferromagnetic superexchange coupling, J, between the localized spins. It is shown that the de-stabilization of the ferromagnetic ground state with increasing J leads to phase…
The two-dimensional Heisenberg exchange model with out-of-plane anisotropy and a Dzyaloshinskii-Moriya interaction is employed to investigate the lifetime and stability of antiferromagnetic (AFM) skyrmions as a function of temperature and…
Excitation spectra of square lattice Heisenberg antiferromagnets in magnetic fields are investigated by the spin-wave theory. It is pointed out that a rotonlike structure appears in a narrow range of magnetic fields, as a result of strong…
Composite hadronic states exhibit interesting properties in the presence of very intense magnetic fields, such as those conjectured to exist in the vicinity of certain astrophysical objects. We discuss three scenarios. (i) The presence of…
The classical spin-flop is the field-driven first-order reorientation transition in easy-axis antiferromagnets. A comprehensive phenomenological theory of easy-axis antiferromagnets displaying spin-flops is developed. It is shown how the…
Ferromagnetic (FM) manganites, a group of likely half-metallic oxides, are of special interest not only because they are a testing ground of the classical doubleexchange interaction mechanism for the colossal magnetoresistance, but also…
Quantum magnets in two dimensions display strong quantum interaction effects even when magnetically ordered. Using the metal-organic framework material CuF$_2$(D$_2$O)$_2$(pyz), we investigate the field-dependent spin dynamics of the $S =…
Making the assumption that high energy fermions exist in the two dimensional spin-1/2 Heisenberg antiferromagnet we present predictions based on the pi-flux ansatz for the dynamic structure factor when the antiferromagnet is subject to a…
We study the effect of inhomogeneities in the magnetic field on the thermal entanglement of a two spin system. We show that in the ferromagnetic case a very small inhomogeneity is capable to produce large values of thermal entanglement.…