Loading…

Vortex dynamics in the classical two-dimensional antiferromagnetic XY model

We investigate the dynamics of the two-dimensional antiferromagnetic Heisenberg model with easy-plane exchange symmetry by explicitly calculating the dynamic correlation functions S αα( q , w), α = x, y, z. In addition to the spin waves we find also topological excitations, namely vortices which cau...

Full description

Saved in:
Bibliographic Details
Published in:Journal of magnetism and magnetic materials 1992-02, Vol.104, p.766-768
Main Authors: Völkel, A.R., Mertens, F.G., Wysin, G.M., Bishop, A.R.
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We investigate the dynamics of the two-dimensional antiferromagnetic Heisenberg model with easy-plane exchange symmetry by explicitly calculating the dynamic correlation functions S αα( q , w), α = x, y, z. In addition to the spin waves we find also topological excitations, namely vortices which cause a Kosterlitz-Thouless phase transition at T KT. Our main interest is focused on the free vortices just above T KT where we developed a phenomenology based on a dilute gas of noninteracting vortices. With this ansatz we find central peaks in S αα( q , w) which are at different positions in q-space depending on whether the static vortex structure or the deviations from it due to a finite velocity dominates the correlations. We compare these results with a combined Monte Carlo Molecular Dynamics simulation on a 100 × 100 square lattice. We find a good agreement between our theory and the simulations and we obtain from this comparison explicit values for the vortex correlation length and the vortex average velocity.
ISSN:0304-8853
DOI:10.1016/0304-8853(92)90350-W