Role of dimensionality in spontaneous magnon decay: Easy-plane ferromagnet

Abstract

We calculate magnon lifetime in an easy-plane ferromagnet on a tetragonal lattice in transverse magnetic field. At zero temperature magnons are unstable with respect to spontaneous decay into two other magnons. Varying ratio of intrachain to interchain exchanges in this model we consider the effect of dimensionality on spontaneous magnon decay. The strongest magnon damping is found in the quasi-one-dimensional case for momenta near the Brillouin zone boundary. The sign of a weak interchain coupling has a little effect on the magnon decay rate. The obtained theoretical results suggest possibility of experimental observation of spontaneous magnon decay in a quasi-onedimensional ferromagnet CsNiF3. We also find an interesting enhancement of the magnon decay rate for a three-dimensional ferromagnet. The effect is present only for the nearest-neighbor model and is related to effective dimensionality reduction in the two-magnon continuum.

Magnetic quantum criticality in quasi‐one‐dimensional Heisenberg antiferromagnet

“…The experimental values 10.3 K and 0.046 K show that the criterion of smallness of the ratio 0.0045 is actually fulfilled. The Holstein‐Primakoff bozonization of the spin Hamiltonian up to first nonlinear terms shows that their contribution to magnetization is only around 5% of that stemming from noninteracting boson gas .…”

Quantum damping of skyrmion crystal eigenmodes due to spontaneous quasiparticle decay

“…Hence, if instead of a two-dimensional SkX we studied a three-dimensional SkX, e.g., built from stacking SkX layers, we would expect a renormalization of the step. However, this renormalization is not as drastic as that associated with going from one to two dimensions, for which the Van Hove singularity of the two-magnon DOS changes from an inverse square root to the step function [97]. Thus, in general, the overall magnitude of the spontaneous magnon damping is not expected to be considerably smaller in three than in two dimensions.…”

“…In contrast, in three dimensions, the onset is given by a square root (see also Refs. [95,97]). Hence, if instead of a two-dimensional SkX we studied a three-dimensional SkX, e.g., built from stacking SkX layers, we would expect a renormalization of the step.…”

Transversal spin freezing and re-entrant spin glass phases in chemically disordered Fe-containing perovskite multiferroics

“…Ref. 21 and references therein). The equations for L then will be almost similar to (4a) and (4b) except that the interaction is now renormalized by the phase factors e iQr , i.e.…”