Spin-disordered quantum phases in a quasi-one-dimensional triangular lattice
Spin-disordered quantum phases in a quasi-one-dimensional triangular lattice
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准一维三角晶格中的自旋无序量子相
DOI：
10.1038/nphys3359
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发表时间：
2015
期刊：
影响因子：
19.6
通讯作者：
Chisa Hotta and Gunzi Saito
中科院分区：
文献类型：
--
作者：
Yukihiro Yoshida;Hiroshi Ito;Mitsuhiko Maesato;Yasuhiro Shimizu ;Hiromi Hayama; Takaaki Hiramatsu;Yuto Nakamura;Hideo Kishida;Takashi Koretsune;Chisa Hotta and Gunzi Saito
巨大的量子涨落将固体中的自旋驱动成磁性无序的相，而不仅仅是顺磁性的。这类系统包括价键晶体和量子自旋液体，其中自旋单态--纠缠自旋对的基本单位--分别形成固体和液体。在这两个阶段，几何上的挫折预计都会起到作用。到目前为止，已经发现的候选量子自旋液体材料很少，包括有机Mott绝缘体κ-(Et)2Cu2(CN)3，它是基于规则三角形晶格的。在这里，我们报道了一种具有不同几何结构的材料κ-(Et)2B(CN)4-一个高度扭曲的准一维三角晶格。在这个扭曲的晶格上，磁化率遵循自旋1/2海森堡模型。该材料在较宽的温度范围内保持了具有增强量子涨落的磁无序Mott绝缘态，并在5K下经历了向自旋间隙相的转变。
Large quantum fluctuations drive the spins in solids into magnetically disordered phases that are not simply paramagnetic. This class of system includes the valence bond crystals and quantum spin liquids, in which spin singlets—the basic unit of entangled pairs of spins—form solids and liquids, respectively. In both phases, geometrical frustration is expected to play a role. So far, very few candidate quantum-spin-liquid materials have been found, including an organic Mott insulator, κ-(ET)2Cu2(CN)3, which is based on a regular triangular lattice. Here, we report a material, κ-(ET)2B(CN)4, with different geometry—a highly distorted quasi-one-dimensional triangular lattice. The magnetic susceptibility follows that of the spin-1/2 Heisenberg model on this distorted lattice. The material sustains a magnetically disordered Mott insulating state with enhanced quantum fluctuations over a wide temperature range, and undergoes a transition into a spin-gapped phase at 5 K.