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...
Saved in:
Published in: | Journal of magnetism and magnetic materials 1992-02, Vol.104, p.766-768 |
---|---|
Main Authors: | , , , |
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!
|
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 |