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arXiv 0904.0123cond-mat.str-elcond-mat.stat-mech
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具有弱限制自旋子的量子磁体:多重长度标度和量子杂质

Quantum magnets with weakly confined spinons: Multiple length scales and quantum impurities

R. L. Doretto, Matthias Vojta

摘要:

在具有强量子涨落的磁体中,可以实现具有或不具有自旋子激发限制的顺磁基态。在这里,我们讨论了在约束-解除约束转变附近的约束相的物理学:这种状态,可能与许多受抑自旋系统有关,其特征在于多个长度尺度:除了磁相关长度之外,可以定义约束长度,可以探测,例如,通过非磁性杂质附近的局部静态测量。我们通过对二聚自旋链的显式计算来说明这些想法,但我们的定性结果在更高的维度上也是有效的。特别是,我们研究交叉从弱到强约束可见的反铁磁极化云周围的非磁性杂质。我们还讨论了杂质之间的有效磁相互作用,相关的杂质诱导的磁秩序,和核磁共振和中子散射实验的后果。

英文摘要:

In magnets with strong quantum fluctuations, paramagnetic ground states with or without confinement of spinon excitations can be realized. Here we discuss the physics of the confined phase in the vicinity of a confinement--deconfinement transition: This regime, likely relevant to a multitude of frustrated spin systems, is characterized by multiple length scales: In addition to the magnetic correlation length, a confinement length can be defined, which can be probed, e.g., by local static measurements near non-magnetic impurities. We illustrate the ideas by explicit calculations for dimerized spin chains, but our qualitative results remain valid in higher dimensions as well. In particular, we study crossover from weak to strong confinement visible in the antiferromagnetic polarization cloud around a non-magnetic impurity. We also discuss the effective magnetic interaction between impurities, relevant for impurity-induced magnetic order, and consequences for nuclear magnetic resonance and neutron scattering experiments.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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