arXiv:1109.0063 · Physical Review B
Spin-chirality separation and S3 symmetry breaking in the magnetization plateau of the quantum spin tube
Kouichi Okunishi, Masahiro Sato, Tôru Sakai, Kiyomi Okamoto, Chigak Itoi
Abstract
We study the magnetization plateau state of the three-leg spin-$\frac{1}{2}$ tube in the strong rung coupling region, where ${S}_{3}$ symmetry breaking and the low-energy chirality degree of freedom play crucial roles. On the basis of the effective chirality model and density matrix renormalization group, we clarify that, as the leg coupling increases, the chirality liquid with gapless nonmagnetic excitations, the spin-imbalance phase, and the vector-spin-chirality ordered phase emerge without closing the plateau spin gap. The relevance of these results to experiments is also discussed.