Spin Gap of the Three-Leg S=3/2Heisenberg Tube
Spin Gap of the Three-Leg S=3/2Heisenberg Tube
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三足管的自旋间隙S=3/2海森堡
DOI：
10.1103/physrevb.83.224425
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
and Y. Ohta
中科院分区：
文献类型：
--
作者：
S. Nishimoto;Y. Fuji;and Y. Ohta
利用密度矩阵重整化群方法研究了三腿直海森堡管的基态性质。我们发现，自旋激发间隙与自发二聚开放的整个耦合制度，如在三腿直海森堡管。然而，与直管的情况相反，差距随着横档耦合的增加而增加得非常缓慢，并且在弱耦合和中等耦合区域中，间隙的大小仅为腿交换相互作用的几分之一或更小。因此，我们认为，除非横档耦合是远远大于腿耦合，差距可能是很难观察到的实验。我们还计算了量子化的Berry相，表明存在三种不同的价键固体状态依赖于腿和横档耦合的比例。
The ground-state properties of the three-legstraight Heisenberg tube are studied using the density-matrix renormalization group method. We find that the spin-excitation gap associated with a spontaneous dimerization opens for the whole coupling regime, as seen in the three-legstraight Heisenberg tube. However, in contrast to the case of thestraight tube, the gap increases very slowly with increasing the rung coupling, and its size is only a fewor less of the leg exchange interaction in the weak- and intermediate-coupling regimes. We thus argue that, unless the rung coupling is substantially larger than the leg coupling, the gap may be quite hard to be observed experimentally. We also calculate the quantized Berry phase to show that there exist three kinds of valence-bond-solid states depending on the ratio of leg and rung couplings.