Striped phase in a quantum XY model with ring exchange.
Striped phase in a quantum XY model with ring exchange.
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DOI：
10.1103/physrevlett.89.247201
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发表时间：
2002-05
影响因子：
8.6
通讯作者：
A. Sandvik;S. Daul;R. 4. Singh;D. Scalapino
中科院分区：
文献类型：
--
作者：
A. Sandvik;S. Daul;R. 4. Singh;D. Scalapino
本文给出了具有标准最近邻耦合J和四自旋环交换项K的正方晶格S=1/2XY模型的量子Monte Carlo结果。增加K/J，我们发现基态自旋刚度消失在一个临界点，在该临界点处的自旋间隙打开和条纹键元序出现。在更高的K/J下，该相变得不稳定，并且系统产生交错磁化。我们讨论了这些阶段之间的量子相变。
We present quantum Monte Carlo results for a square-lattice S=1/2 XY model with a standard nearest-neighbor coupling J and a four-spin ring exchange term K. Increasing K/J, we find that the ground state spin stiffness vanishes at a critical point at which a spin gap opens and a striped bond-plaquette order emerges. At still higher K/J, this phase becomes unstable and the system develops a staggered magnetization. We discuss the quantum phase transitions between these phases.