Effective spin-wave action for ordered Heisenberg antiferromagnets in a magnetic field
Abstract
We derive the effective long-wavelength Euclidean action for the antiferromagnetic spin-waves of ordered quantum antiferromagnets subject to a uniform magnetic field. We point out that the magnetic field dependence of the spin-wave dispersion predicted by the usual O(3)-quantum nonlinear sigma model disagrees with spin-wave theory. We argue that the nonlinear sigma model does not take into account all relevant spin-wave interactions and derive a modified effective action for the long-wavelength spin-waves which contains an additional quartic interaction. At zero temperature the corresponding vertex is relevant in the renormalization group sense below three dimensions.
Keywords
Cite
@article{arxiv.cond-mat/0511706,
title = {Effective spin-wave action for ordered Heisenberg antiferromagnets in a magnetic field},
author = {Nils Hasselmann and Florian Schuetz and Ivan Spremo and Peter Kopietz},
journal= {arXiv preprint arXiv:cond-mat/0511706},
year = {2007}
}
Comments
4 pages, 1 eps figure; proceedings of the symposium on "Spin- and charge-correlations in molecule-based materials", October 2005, Koenigstein (Taunus), Germany