Using first-principles calculations and micromagnetic simulations, we systematically investigate the magnetic properties of two-dimensional Janus chromium dichalcogenides ($\mathrm{Cr}X\mathrm{Te}, X=\mathrm{S}$, Se) under strain. We find that the CrSTe monolayer has high Curie temperature ($T_c$) of 295 K and an out-of-plane magnetic anisotropy. The CrSeTe monolayer has large Dzyaloshinskii-Moriya interaction (DMI) which can host chiral Néel domain wall (DW), and under an external magnetic field, the skyrmion states can be induced. As tensile strain increases, ferromagnetic exchange coupling and perpendicular magnetic anisotropy of Janus $\mathrm{Cr}X\mathrm{Te}$ monolayers both increase significantly, and the magnitude of DMI is reduced, which results in the giant ferromagnetism enhancement. Interestingly, for CrSeTe monolayer, distinct spin textures from chiral DW to uniform ferromagnetic states are induced under tensile strain. Moreover, the diameter and density of skyrmions in CrSeTe can be tuned by the amplitude of external magnetic field and strain. These findings highlight that the Janus $\mathrm{Cr}X\mathrm{Te}$ monolayers as good candidates for spintronic nanodevices.

中文翻译：

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二维Janus铬二卤化铬中的应变可调铁磁性和手性自旋结构

使用第一性原理计算和微磁模拟，我们系统地研究了二维Janus铬二卤化铬的磁性。$铬X特， X=\mathrm{小号}$（Se）。我们发现CrSTe单层具有较高的居里温度（${Ť}_C$）为295 K，并且具有面外磁各向异性。CrSeTe单分子膜具有较大的Dzyaloshinskii-Moriya相互作用（DMI），可以承载手性Néel畴壁（DW），并且在外部磁场下可以诱导天rm离子状态。随着拉伸应变的增加，Janus的铁磁交换耦合和垂直磁各向异性$铬X特$单层都显着增加，并且DMI的大小减小，这导致巨大的铁磁性增强。有趣的是，对于CrSeTe单层，在拉伸应变下会产生从手性DW到均匀铁磁态的不同自旋织构。此外，可以通过外部磁场的振幅和应变来调节CrSeTe中的天空离子的直径和密度。这些发现突显了Janus$铬X特$ 单层是自旋电子纳米器件的良好候选者。