Continuum in the Excitation Spectrum of the S=1 Compound CsNiCl_3
arXiv:cond-mat/0205234 · doi:10.1140/epjb/e2003-00129-0
Abstract
Recent neutron scattering experiments on CsNiCl_3 reveal some features which are not well described by the nonlinear sigma model nor by numerical simulations on isolated S=1 spin chains. In particular, in real systems the intensity of the continuum of multiparticle excitations, at T=6K, is about 5 times greater than predicted. Also the gap is slightly higher and the correlation length is smaller. We propose a theoretical scenario where the interchain interaction is approximated by a staggered magnetic field, yielding to a correct prediction of the observed quantities.
4 pages, 2 figures (.eps), RevTex