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arXiv · 1903.04934

Magnetoelastic couplings in the deformed Kagomé quantum spin lattice of volborthite

Akihiko Ikeda·Shunsuke Furukawa·Oleg Janson·Yasuhiro H. Matsuda·Shojiro Takeyama·Takeshi Yajima·Zenji Hiroi·Hajime Ishikawa
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Abstract

Microscopic spin interactions on a deformed Kagomé lattice of volborthite are investigated through magnetoelastic couplings. A negative longitudinal magnetostriction $ΔL<0$ in the $b$ axis is observed, which depends on the magnetization $M$ with a peculiar relation of $ΔL/L \propto M^{1.3}$. 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.

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Akihiko Ikeda, Shunsuke Furukawa, Oleg Janson, Yasuhiro H. Matsuda, Shojiro Takeyama, Takeshi Yajima, Zenji Hiroi, Hajime Ishikawa. 2019-03-12. Magnetoelastic couplings in the deformed Kagomé quantum spin lattice of volborthite. https://doi.org/10.1103/physrevb.99.140412

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