Spin-induced negative thermal expansion and spin-phonon coupling in van der Waals material CrBr3
Spin-induced negative thermal expansion and spin-phonon coupling in van der Waals material CrBr3
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DOI：
10.1038/s41535-021-00318-5
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发表时间：
2021-03-02
影响因子：
5.7
通讯作者：
Savenko, B. N.
中科院分区：
文献类型：
--
作者：
Kozlenko, D. P.;Lis, O. N.;Savenko, B. N.
二维范德华（vdW）磁体在原子薄极限下保持磁序，表现出具有挑战性的物理现象，它们被认为是构建先进自旋电子学和纳米电子器件的潜在构建模块。在这里，我们提出了晶格体积和 vdW 层的负热膨胀以及强自旋声子耦合效应的实验证据，这些效应是由 vdW 材料 CrBr3 中长程铁磁有序的形成引起的。中子和X射线衍射测量揭示了居里温度（T-C）附近晶格参数以及原子间距离和角度的异常温度变化。拉曼光谱测量发现，大多数观察到的振动模式的频率显着上升，并且其半峰全宽在 T-C 以下出现不寻常的反转展宽。
The two-dimensional van der Waals (vdW) magnets retaining magnetic order in atomically thin limit demonstrate challenging physical phenomena and they are considered as prospective building blocks for construction of advanced spintronics and nanoelectronics devices. Here, we present experimental evidence for negative thermal expansion of lattice volume and vdW layers and strong spin-phonon coupling effects, caused by formation of the long-range ferromagnetic order in the vdW material CrBr3. The neutron and X-ray diffraction measurements revealed anomalous temperature variation of lattice parameters and interatomic distances and angles in the vicinity of Curie temperature (T-C). A pronounced rise of the frequencies of the most of the observed vibrational modes and unusual reversal broadening of their full widths at half maximum below T-C was found from Raman spectroscopy measurements.