Phase Transitions in Bilayer Heisenberg Model with General Couplings
Abstract
The ground state properties and phase diagram of the bilayer square-lattice Heisenberg model are studied in a broad parameter space of intralayer exchange couplings, assuming an antiferromagnetic coupling between constituent layers. In the classical limit, the model exhibits three phases: two of these are ordered phases specified by the ordering wave vectors (pi,pi;pi) and (0,0;pi), where the third component of each indecates the antiferromagnetic orientation between layers, while another one is a canted phase, stabilized by competing interactions. The effects of quantum fluctuations in the model with S=1/2 have been explored by means of dimer mean-field theory, small-system exact diagonalization, and high-order perturbation expansions about the interlayer dimer limit.
Keywords
Cite
@article{arxiv.cond-mat/9707156,
title = {Phase Transitions in Bilayer Heisenberg Model with General Couplings},
author = {Yasuhiro Matsushita and Martin P. Gelfand and Chikara Ishii},
journal= {arXiv preprint arXiv:cond-mat/9707156},
year = {2009}
}
Comments
15 pages, LaTeX, 12 figures, uses jpsj.sty, revised version: some discussion to a related model and references added, submitted to the Journal of the Physical Society of Japan