Yamaguchi Hironori, Okada Masataka, Kono Yohei, Kittaka Shunichiro, Sakakibara Toshiro, Okabe Toshiki, Iwasaki Yoshiki, Hosokoshi Yuko
Department of Physical Science, Osaka Prefecture University, Osaka, 599-8531, Japan.
Institute for Solid State Physics, The University of Tokyo, Chiba, 277-8581, Japan.
Sci Rep. 2017 Nov 23;7(1):16144. doi: 10.1038/s41598-017-16431-0.
Quantum entanglement in magnetic materials is expected to yield a quantum spin liquid (QSL), in which strong quantum fluctuations prevent magnetic ordering even at zero temperature. This topic has been one of the primary focuses of condensed-matter science since Anderson first proposed the resonating valence bond state in a certain spin-1/2 frustrated magnet in 1973. Since then, several candidate materials featuring frustration, such as triangular and kagome lattices, have been reported to exhibit liquid-like behavior. However, the mechanisms that stabilize the liquid-like states have remained elusive. Here, we present a QSL state in a spin-1/2 honeycomb lattice with randomness in the exchange interaction. That is, we successfully introduce randomness into the organic radial-based complex and realize a random-singlet (RS) state (or valence bond glass). All magnetic and thermodynamic experimental results indicate the liquid-like behaviors, which are consistent with those expected in the RS state. Our results suggest that the randomness or inhomogeneity in the actual systems stabilize the RS state and yield liquid-like behavior.
磁性材料中的量子纠缠有望产生一种量子自旋液体（QSL），在这种液体中，即使在零温度下，强烈的量子涨落也会阻止磁有序。自1973年安德森首次在某种自旋1/2阻挫磁体中提出共振价键态以来，这个话题一直是凝聚态物理科学的主要焦点之一。从那时起，据报道，几种具有阻挫特性的候选材料，如三角形和 Kagome 晶格，表现出类似液体的行为。然而，稳定类似液体状态的机制仍然难以捉摸。在这里，我们在具有交换相互作用随机性的自旋1/2蜂窝晶格中呈现了一种QSL态。也就是说，我们成功地将随机性引入基于有机径向的配合物中，并实现了一种随机单重态（RS）态（或价键玻璃）。所有的磁性和热力学实验结果都表明了类似液体的行为，这与RS态中预期的行为一致。我们的结果表明，实际系统中的随机性或不均匀性稳定了RS态并产生了类似液体的行为。
