Jiang Ningxin, Ramanathan Arun, Bacsa John, La Pierre Henry S
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.
Nuclear and Radiological Engineering Program, School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
Nat Chem. 2020 Aug;12(8):691-696. doi: 10.1038/s41557-020-0490-8. Epub 2020 Jun 29.
The kagome lattice, composed of a planar array of corner-sharing triangles, is one of the most geometrically frustrated lattices. The realization of a spin S = 1/2 kagome lattice antiferromagnet is of particular interest because it may host an exotic form of matter, a quantum spin liquid state, which shows long-range entanglement and no magnetic ordering down to 0 K. A few S = 1/2 kagome lattice antiferromagnets exist, typically based on Cu, d compounds, though they feature structural imperfections. Herein, we present the synthesis of (CHNH)NaTiF, which comprises an S = 1/2 kagome layer that exhibits only one crystallographically distinct Ti, d site, and one type of bridging fluoride. A static positional disorder is proposed for the interlayer CHNH. No structural phase transitions were observed from 1.8 K to 523 K. Despite its spin-freezing behaviour, other features-including its negative Curie-Weiss temperature and a lack of long-range ordering-imply that this compound is a highly frustrated magnet with unusual magnetic phase behaviours.
由角共享三角形的平面阵列组成的 Kagome 晶格是几何阻挫最严重的晶格之一。自旋 S = 1/2 的 Kagome 晶格反铁磁体的实现特别令人感兴趣，因为它可能包含一种奇异的物质形式，即量子自旋液体状态，这种状态在低至 0 K 时表现出长程纠缠且没有磁有序。存在一些 S = 1/2 的 Kagome 晶格反铁磁体，通常基于铜的 d 化合物，尽管它们具有结构缺陷。在此，我们展示了(CHNH)NaTiF 的合成，它包含一个 S = 1/2 的 Kagome 层，该层仅呈现一个晶体学上不同的 Ti、d 位点和一种类型的桥连氟化物。对于层间 CHNH 提出了静态位置无序。从 1.8 K 到 523 K 未观察到结构相变。尽管它具有自旋冻结行为，但其其他特征——包括负的居里 - 外斯温度和缺乏长程有序——意味着该化合物是一种具有异常磁相行为的高度阻挫磁体。
