First-order quantum phase transition in the orthogonal-dimer spin chain
Abstract
We investigate the low-energy properties of the orthogonal-dimer spin chain characterized by a frustrated dimer-plaquette structure. When the competing antiferromagnetic couplings are varied, the first-order quantum phase transition occurs between the dimer and the plaquette phases, which is accompanied by nontrivial features due to frustration: besides the discontinuity in the lowest excitation gap at the transition point, a sharp level-crossing occurs for the spectrum in the plaquette phase. We further reveal that the plateau in the magnetization curve at 1/4 of the full moment dramatically changes its character in the vicinity of the critical point. It is argued that the first-order phase transition in this system captures some essential properties found in the two-dimensional orthogonal-dimer model proposed for .
Cite
@article{arxiv.cond-mat/0003437,
title = {First-order quantum phase transition in the orthogonal-dimer spin chain},
author = {Akihisa Koga and Kouichi Okunishi and Norio Kawakami},
journal= {arXiv preprint arXiv:cond-mat/0003437},
year = {2009}
}
Comments
7 pages, submitted to Phys. Rev. B