We study the correlation <σ0zσnz> for the XXZ chain in the massless attractive (ferromagnetic) region at positive temperatures by means of a numerical study of the quantum transfer matrix. We find that there is a range of temperature where the behavior of the correlation for large separations is oscillatory with an incommensurate period which depends on temperature.
@article{arxiv.cond-mat/9812012,
title = {Temperature dependent spatial oscillations in the correlations of the XXZ spin chain},
author = {Klaus Fabricius and Andreas Klümper and Barry M. McCoy},
journal= {arXiv preprint arXiv:cond-mat/9812012},
year = {2016}
}