Three-Dimensional Ordering in Weakly Coupled Antiferromagnetic Ladders and Chains
Abstract
A theoretical description is presented for low-temperature magnetic-field induced three-dimensional (3D) ordering transitions in strongly anisotropic quantum antiferromagnets, consisting of weakly coupled antiferromagnetic spin-1/2 chains and ladders. First, effective continuum field theories are derived for the one-dimensional subsystems. Then the Luttinger parameters, which determine the low-temperature susceptibilities of the chains and ladders, are calculated from the Bethe ansatz solution for these effective models. The 3D ordering transition line is obtained using a random phase approximation for the weak inter-chain (inter-ladder) coupling. Finally, considering a Ginzburg criterion, the fluctuation corrections to this approach are shown to be small. The nature of the 3D ordered phase resembles a Bose condensate of integer-spin magnons. It is proposed that for systems with higher spin degrees of freedom, e.g. N-leg spin-1/2 ladders, multi-component condensates can occur at high magnetic fields.
Cite
@article{arxiv.cond-mat/9910259,
title = {Three-Dimensional Ordering in Weakly Coupled Antiferromagnetic Ladders and Chains},
author = {Stefan Wessel and Stephan Haas},
journal= {arXiv preprint arXiv:cond-mat/9910259},
year = {2009}
}
Comments
RevTex, 18 pages with 7 figures