In the search for spin-1/2 kagome antiferromagnets, the mineral volborthite has recently been the subject of experimental studies [Hiroi et al.,2001]. It has been suggested that the magnetic properties of this material are described by a spin-1/2 Heisenberg model on the kagome lattice with spatially anisotropic exchange couplings. We report on investigations of the Sp(N) symmetric generalisation of this model in the large N limit. We obtain a detailed description of the dependence of possible ground states on the anisotropy and on the spin length S. A fairly rich phase diagram with a ferrimagnetic phase, incommensurate phases with and without long range order and a decoupled chain phase emerges.
@article{arxiv.cond-mat/0608393,
title = {Spatially anisotropic Heisenberg Kagome antiferromagnet},
author = {W. Apel and T. Yavors'kii and H. -U. Everts},
journal= {arXiv preprint arXiv:cond-mat/0608393},
year = {2009}
}
Comments
6 pages, 6 figures, proceedings of the HFM2006 conference, to appear in a special issue of J. Phys.: Condens. Matter