中山大学设计出超凡二维磁性材料:铬基硫卤化物

Fig. 1 Crystal structure and magnetic properties of CrYX.

Editorial Summary

Multifunctional magnetic materials: Ferromagnetism, QAHE, valley splitting and skyrmions

Magnetic proximity effect can give rise to diverse outstanding functionalities in spintronic, valleytronic and optoelectronic devices when two-dimensional (2D) van der Waals (vdW) magnetic materials are assembled with other functional materials. Therefore, enlarging the spin polarizations in the outer anions of 2D vdW magnetic materials will strengthen the magnetic proximity effect. 

Fig. 3 Electronic and topological properties of CrSBr/BS/CrSBr.

Considering the feasibility of selecting a suitable pair of anions in Janus vdW materials, a team led by Associated Prof. Yusheng Hou from School of physics, Sun Yat-Sen University and Prof. Ruqian Wu from Department of physics and astronomy, University of California Irvine designed a class of ferromagnetic semiconductors CrSX (X=Cl, Br, I) with large magnetic moments on S^2-anions, the largest for 2D ferromagnetic semiconductors reported so far. Based on these 2D ferromagnetic semiconductors with high Curie temperatures, the long-sought large-gap Quantum anomalous Hall effect (QAHE) and a sizable valley splitting are realized through the magnetic proximity effect in vdW heterostructures CrSBr/Bi₂Se₃/CrSBr and MoTe₂/CrSBr, respectively. Additionally, Monte Carlo simulations show that the large Dzyaloshinskii–Moriya interactions lead to magnetic skyrmion states in CrTeX (X=Cl, Br, I) under an appropriate external magnetic field. Their results demonstrate the promising applications of the multifunctional 2D vdW Janus magnet Cr-based dichalcogenide halides in topological electronic and valleytronic devices. This article was recently published in npj Computational Materials 8: 120 (2022). 

Fig. 4 Electronic and topological properties of CrSBr/MoTe2.

原文Abstract及其翻译

Multifunctional two-dimensional van der Waals Janus magnet Cr-based dichalcogenide halides (多功能二维范德瓦尔斯雅努斯磁性材料：铬基硫卤化物)

Yusheng Hou, Feng Xue, Liang Qiu, Zhe Wang and Ruqian Wu 

摘要 二维范德维尔斯雅努斯（Janus）材料及其异质结为设计新颖的功能提供了广阔的平台。本研究基于范德维尔斯雅努斯单层磁性材料铬基硫卤化物CrYX（Y=硫、硒、碲; X=氯、溴、碘）的第一性原理计算结果，发现CrSX（X=氯、溴、碘）是难得的具有面外磁化和高居里温度的铁磁半导体。更令人兴奋的是，得益于配体阴离子S^2-上的大磁矩，大带隙的量子反常霍尔效应和较大的能谷劈裂可以通过磁临近效应分别在范德维尔斯异质结CrSBr/Bi₂Se₃/CrSBr 和 MoTe₂/CrSBr中实现。此外，本研究还表明在外加磁场下，大的Dzyaloshinskii–Moriya相互作用可以在CrTeX（X=氯、溴、碘）中诱发磁斯格明子。本研究结果揭示了多功能的二维范德维尔斯雅努斯磁性材料铬基硫卤化物在拓扑电子学和能谷电子学器件中的诱人应用前景。

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