Solitons in the linear-chain antiferromagnet

Abstract

We show that in quasi-one-dimensional antiferromagnets, sine-Gordon solitons should be present as thermal excitations under a range of conditions outlined here. For a class of model spin Hamiltonians which include the influence of a transverse Zeeman field and easy-plane anisotropy, we provide explanations for the soliton rest energy, and its limiting velocity. Also, we examine the statistical mechanics of these systems with emphasis on the form of the soliton contribution to the free energy.