Han Yue-Tong, Ji Wei-Xiao, Wang Pei-Ji, Li Ping, Zhang Chang-Wen
School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China.
Nanoscale. 2023 Apr 6;15(14):6830-6837. doi: 10.1039/d2nr06870b.
The Dzyaloshinskii-Moriya interaction (DMI), which only exists in noncentrosymmetric systems, plays an important role in the formation of exotic chiral magnetic states. However, the absence of the DMI occurs in most two-dimensional (2D) magnetic materials due to their intrinsic inversion symmetry. Here, by using first-principles calculations, we demonstrate that a significant DMI can be obtained in a series of Janus monolayers of dichalcogenides XSeTe (X = Nb, Re) in which the difference between Se and Te on the opposite sides of X breaks the inversion symmetry. Remarkably, the DMI amplitudes of NbSeTe (1.78 meV) and ReSeTe (4.82 meV) are larger than the experimental value of Co/graphene (0.16 meV), and NbSeTe and ReSeTe monolayers have a high Curie temperature of 1023 K and 689 K, respectively. Through the micromagnetic simulation of XSeTe (X= Nb, Re) simulations, we also find that the ReSeTe monolayer can performance for skyrmion states by applying an external magnetic field, and importantly, the skyrmion states can be regulated and controlled under external strain. The findings pave the way for device concepts using chiral magnetic structures in specially designed 2D ferromagnetic materials.
仅存在于非中心对称系统中的Dzyaloshinskii-Moriya相互作用（DMI）在奇异手性磁态的形成中起着重要作用。然而，由于大多数二维（2D）磁性材料具有固有的反演对称性，因此不存在DMI。在此，通过第一性原理计算，我们证明在一系列二硫属化物XSeTe（X = Nb，Re）的Janus单层中可以获得显著的DMI，其中X相对两侧的Se和Te之间的差异打破了反演对称性。值得注意的是，NbSeTe（1.78 meV）和ReSeTe（4.82 meV）的DMI振幅大于Co/石墨烯的实验值（0.16 meV），并且NbSeTe和ReSeTe单层分别具有1023 K和689 K的高居里温度。通过对XSeTe（X = Nb，Re）的微磁模拟，我们还发现ReSeTe单层通过施加外部磁场可以表现出斯格明子态，重要的是，斯格明子态可以在外部应变下进行调控。这些发现为在特殊设计的二维铁磁材料中使用手性磁结构的器件概念铺平了道路。
