Magnetoelastic couplings in the deformed kagome quantum spin lattice of volborthite
Magnetoelastic couplings in the deformed kagome quantum spin lattice of volborthite
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DOI：
10.1103/physrevb.99.140412
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发表时间：
2019-03
影响因子：
3.7
通讯作者：
A. Ikeda;S. Furukawa;O. Janson;Y. Matsuda;S. Takeyama;T. Yajima;Z. Hiroi;H. Ishikawa
中科院分区：
文献类型：
--
作者：
A. Ikeda;S. Furukawa;O. Janson;Y. Matsuda;S. Takeyama;T. Yajima;Z. Hiroi;H. Ishikawa
通过磁弹性耦合研究了变形Kagome晶格上的微观自旋相互作用。在$B$轴上观察到一个负的纵向磁致伸缩$\Delta L<0$，它与磁化强度$M$有一个特殊的关系$\Delta L/L \propto M^{1.3}$。基于交换伸缩模型，认为负磁致伸缩源于Cu-O-Cu链在$B$轴上的类似于缩放的晶格变化，而这种特殊的依赖性则源于局域自旋关联.这个想法是支持DFT+$U$计算模拟晶格变化和自旋相关的有限尺寸计算，表明最近提出的耦合三聚体模型是一个合理的。
Microscopic spin interactions on a deformed Kagome lattice of volborthite are investigated through magnetoelastic couplings. A negative longitudinal magnetostriction $\Delta L<0$ in the $b$ axis is observed, which depends on the magnetization $M$ with a peculiar relation of $\Delta L/L \propto M^{1.3}$. Based on the exchange striction model, it is argued that the negative magnetostriction originates from a pantograph-like lattice change of the Cu-O-Cu chain in the $b$ axis, and that the peculiar dependence arises from the local spin correlation. This idea is supported by DFT+$U$ calculations simulating the lattice change and a finite-size calculation of the spin correlation, indicating that the recently proposed coupled-trimer model is a plausible one.