论文标题
量子旋转候选候选者中低能激发的非本地效应Cu $ _3 $ Zn（oh）$ _ 6 $ fbr
Nonlocal effects of low-energy excitations in quantum-spin-liquid candidate Cu$_3$Zn(OH)$_6$FBr
论文作者
论文摘要
我们系统地研究了二维Kagome Antiferromagnet的低温特异性热量，Cu $ _ {3} $ Zn（OH）$ _ 6 $ fbr。特定的热量在低温下表现出$ t^{1.7} $依赖性，并在其上方表现出类似肩膀的功能。我们构建了$ z_2 $量子自旋液体的微观晶格模型，并执行大规模量子蒙特卡洛模拟，以表明上述行为来自于gaped gaped andyons和磁性杂质的贡献。令人惊讶的是，我们发现与肩部相关的熵随晶粒尺寸$ d $迅速减小，尽管该系统是最低温度的顺磁性。虽然可以简单地通过核心壳图片来解释，因为内部状态的贡献消失在表面附近，但5.9 nm的壳宽度排除了任何琐碎的解释。如此大的长度标准表示量子旋转液体候选者中量子纠缠激发的非局部性的相干长度，类似于超导体中皮帕德的相干长度。因此，我们的方法对拓扑顺序的无形量子状态提供了新的实验探测。
We systematically study the low-temperature specific heats for the two-dimensional kagome antiferromagnet, Cu$_{3}$Zn(OH)$_6$FBr. The specific heat exhibits a $T^{1.7}$ dependence at low temperatures and a shoulder-like feature above it. We construct a microscopic lattice model of $Z_2$ quantum spin liquid and perform large-scale quantum Monte Carlo simulations to show that the above behaviors come from the contributions from gapped anyons and magnetic impurities. Surprisingly, we find the entropy associated with the shoulder decreases quickly with grain size $d$, although the system is paramagnetic to the lowest temperature. While this can be simply explained by a core-shell picture in that the contribution from the interior state disappears near the surface, the 5.9-nm shell width precludes any trivial explanations. Such a large length scale signifies the coherence length of the nonlocality of the quantum entangled excitations in quantum spin liquid candidate, similar to Pippard's coherence length in superconductors. Our approach therefore offers a new experimental probe of the intangible quantum state of matter with topological order.
