Eur. Phys. J. B 32, 489-493 (2003)
https://doi.org/10.1140/epjb/e2003-00129-0

Multiparticle continuum in the excitation spectrum of the S=1 compound CsNiCl₃

Physics Department, University of Bologna, INFM and INFN, 6/2 v.le B. Pichat, 40127, Bologna, Italy

Corresponding author: ^a roncaglia@bo.infn.it

Received: 2 October 2002
Revised: 19 March 2003
Published online: 7 May 2003

Abstract

Recent neutron scattering experiments on CsNiCl₃ reveal some features that are not well described by the standard nonlinear σ model, nor by numerical simulations, for isolated S=1 spin chains. In particular, in real systems at the antiferromagnetic point of the Brillouin zone, the intensity of the continuum of multiparticle excitations, at T = 6 K, is about 5 times greater than predicted. Also, the spin gap is higher and the correlation length is smaller than predicted. We propose a theoretical scenario where the interchain interaction is approximated by an effective staggered magnetic field, and that yields a correct prediction for the observed quantities.