Temperature dependencies of gap energies and magnon lifetimes are measured in the quasi-1-dimensional S=1/2 gapped quantum magnets IPA-CuCl3 and Sul-Cu2Cl4 using inelastic neutron scattering. The results are compared to those found in literature for S=1 Haldane spin chain materials and to theoretical calculations for the O(3)- and O(N)- quantum non-linear sigma-models. It is found that when the T=0 energy gap Delta is used as the temperature scale, all experimental and theoretical curves are identical to within system-dependent but temperature-independent scaling factors of the order of unity. This quasi-universality extends over a surprising broad T range, at least up to kappa T ~ 1.5 Delta.
@article{arxiv.0711.4094,
title = {Quasi-universal finite-$T$ scaling in gapped one-dimensional quantum magnets},
author = {A. Zheludev and V. O. Garlea and L. -P. Regnault and H. Manaka and A. Tsvelik and J. -H. Chung},
journal= {arXiv preprint arXiv:0711.4094},
year = {2008}
}