Topological Excitations on a Classical 2D Easy-Axis Heisenberg Model

Abstract

We study the properties of single solitons (magnon droplets) in the classical, two-dimensional anisotropic Heisenberg model with easy-axis symmetry. We choose a model with anisotropic exchange interactions, in contrast to the well known models with on-site anisotropy. We show that in our model we have formally the same integrals of motion. In the case of a soliton with vorticity q = 1 we numerically solve the equations of motion in the continuum limit, using a shooting method. We find that the radius of the solitons is a free parameter and investigate the dependency of the precession frequency of the spins on the anisotropy of the system and on the radius of the soliton. We compare our results with spin dynamics simulations and find a good agreement in a large range of the anisotropy. Finally, we discuss the limits of the applicability of the continuum theory. 1 Introduction We consider the classical anisotropic Heisenberg ferromagnet in two dimensions H = \GammaJ X nm (S n x S..