Coupling of Crystal Structure and Magnetism in the Layered, Ferromagnetic Insulator CrI3
Coupling of Crystal Structure and Magnetism in the Layered, Ferromagnetic Insulator CrI3
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DOI：
10.1021/cm504242t
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发表时间：
2015-01-27
影响因子：
8.6
通讯作者：
Sales, Brian C.
中科院分区：
文献类型：
--
作者：
McGuire, Michael A.;Dixit, Hemant;Sales, Brian C.
我们研究了 CrI3 单晶的晶体学和磁性，CrI3 是一种易于解理、层状和绝缘的铁磁体，居里温度为 61 K。我们的 X 射线衍射研究表明，在升温时，在 210-220 K 附近会发生一级晶体相变，并具有显着的热滞后。低温结构为菱面体结构（R（3）over bar，BiI3型），高温结构为单斜晶系（C-2/m，AlCl3型）。我们发现了 CrI3 中晶体自由度和磁自由度之间耦合的证据，观察到居里温度下层间距的异常以及结构转变时磁化率的异常。第一性原理计算揭示了正确处理长程层间力的重要性，范德华密度泛函理论在预测晶体结构及其相对稳定性方面表现出色。计算还表明，在块体材料中发现的铁磁有序可能会持续形成单层形式，这表明 CrI3 和其他三卤化铬可能是用于自旋电子和磁电子研究的有前途的材料。
We have examined the crystallographic and magnetic properties of single crystals of CrI3, an easily cleavable, layered and insulating ferromagnet with a Curie temperature of 61 K. Our X-ray diffraction studies reveal a first-order crystallographic phase transition occurring near 210-220 K upon warming, with significant thermal hysteresis. The low-temperature structure is rhombohedral (R (3) over bar, BiI3-type) and the high-temperature structure is monoclinic (C-2/m, AlCl3-type). We find evidence for coupling between the crystallographic and magnetic degrees of freedom in CrI3, observing an anomaly in the interlayer spacing at the Curie temperature and an anomaly in the magnetic susceptibility at the structural transition. First-principles calculations reveal the importance of proper treatment of the long-ranged interlayer forces, and van der Waals density functional theory does an excellent job of predicting the crystal structures and their relative stability. Calculations also suggest that the ferromagnetic order found in the bulk material may persist into monolayer form, suggesting that CrI3 and other chromium trihalides may be promising materials for spintronic and magnetoelectronic research.