We study dynamical properties of the anisotropic triangular quantum antiferromagnet Cs_2CuCl_4. Inelastic neutron scattering measurements have established that the dynamical spin correlations cannot be understood within a linear spin wave analysis. We go beyond linear spin wave theory by taking interactions between magnons into account in a 1/S expansion. We determine the dynamical structure factor and carry out extensive comparisons with experimental data. We find that compared to linear spin wave theory a significant fraction of the scattering intensity is shifted to higher energies and strong scattering continua are present. However, the 1/S expansion fails to account for the experimentally observed large quantum renormalization of the exchange energies.
@article{arxiv.cond-mat/0506667,
title = {Spin dynamics of the quasi two dimensional spin-1/2 quantum magnet Cs_2CuCl_4},
author = {Martin Y. Veillette and Andrew J. A. James and Fabian H. L. Essler},
journal= {arXiv preprint arXiv:cond-mat/0506667},
year = {2007}
}
Comments
13 pages, 11 figures, higher quality figures can be obtained from the authors