Ground-state phase diagram of a spin-1/2 frustrated XXZ ladder
Ground-state phase diagram of a spin-1/2 frustrated XXZ ladder
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DOI：
10.1103/physrevb.106.155106
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发表时间：
2022-06
期刊：
影响因子：
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通讯作者：
T. Ogino;Ryui Kaneko;Satoshi Morita;S. Furukawa
中科院分区：
文献类型：
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作者：
T. Ogino;Ryui Kaneko;Satoshi Morita;S. Furukawa
我们研究了自旋- 12受挫XXZ阶梯的基态相图，其中两个反铁磁链通过竞争阶和对角相互作用，J⊥和J x耦合。先前对各向同性模型的研究表明，腿之间波动诱导的有效二聚体吸引力使柱状二聚体（CD）相在高度受挫的状态J⊥≈2 J x中稳定，特别是对于铁磁性的J⊥，x < 0。通过有效场理论和数值分析，将此分析推广到XXZ模型，得到了丰富的相图。图中包含了四个没有对称破缺的无特征相位：横单线态（RS）和霍尔丹相，以及它们的扭曲变体，RS*和霍尔丹*相，它们在存在某些对称性时都是不同的。值得注意的是，各向同性模型中的Haldane-CD过渡点是XXZ模型中两条过渡线的交叉点，并且在这些线之间出现了条纹N´eel和RS*相。这表明有效二聚体吸引力与交换各向异性之间存在着重要的相互作用。在易平面状态下，四个无特征相位和两个关键相位以一种复杂的方式竞争，这取决于⊥，x的符号。
We study the ground-state phase diagram of a spin- 12 frustrated XXZ ladder, in which two antiferromagnetic chains are coupled by competing rung and diagonal interactions, J ⊥ and J × . Previous studies on the isotropic model have revealed that a fluctuation-induced effective dimer attraction between the legs stabilizes the columnar dimer (CD) phase in the highly frustrated regime J ⊥ ≈ 2 J × , especially for ferromagnetic J ⊥ , × < 0. By means of effective field theory and numerical analyses, we extend this analysis to the XXZ model, and obtain a rich phase diagram. The diagram includes four gapped featureless phases with no symmetry breaking: the rung singlet (RS) and Haldane phases as well as their twisted variants, the RS* and Haldane* phases, which are all distinct in the presence of certain symmetries. Significantly, the Haldane-CD transition point in the isotropic model turns out to be a crossing point of two transition lines in the XXZ model, and the stripe N´eel and RS* phases appear between these lines. This indicates a nontrivial interplay between the effective dimer attraction and the exchange anisotropy. In the easy-plane regime, the four featureless phases and two critical phases are found to compete in a complex manner depending on the signs of J ⊥ , × .