Guan Zhihao, Shen Zhong, Xue Yufei, Zhong Tingting, Wu Xiaoping, Song Changsheng
Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
Longgang Institute of Zhejiang Sci-Tech University, Wenzhou, 325802, China.
Phys Chem Chem Phys. 2023 Sep 20;25(36):24968-24975. doi: 10.1039/d3cp02470a.
Using first-principles calculations, we systematically investigate the electronic properties, chiral skyrmions and bimerons in two-dimensional (2D) Janus CrXY (X, Y = S, Se, Te, Cl, Br, I, and X ≠ Y) monolayers. We found that the categories of nonmagnetic atoms (X and Y in CrXY) determine whether CrXY is a ferromagnetic metal or a semiconductor. Unexpectedly, the CrBrS monolayer of these CrXY materials is a room temperature ferromagnetic semiconductor with a Curie temperature of 303 K, and it possesses an off-plane magnetic anisotropy energy of 0.06 meV. Besides, a strong Dzyaloshinskii-Moriya interaction (DMI) of 3.10 meV is found in CrTeI and is mainly induced by the strong spin-orbit coupling of the nonmagnetic atoms Te(I) rather than that of the magnetic Cr atoms. Furthermore, using micromagnetic simulations, skyrmions can be stabilized in CrSeBr without external magnetic fields. More importantly, the bimerons in CrSeCl with in-plane magnetic anisotropy can be transformed into skyrmions or a ferromagnetic state by controlling the direction of external magnetic fields. Our work investigates fourteen kinds of Janus monolayers, serving as guidelines for materials research on DMI, skyrmions and bimerons.
利用第一性原理计算，我们系统地研究了二维（2D）Janus CrXY（X、Y = S、Se、Te、Cl、Br、I，且X ≠ Y）单层中的电子性质、手性斯格明子和双聚物。我们发现，非磁性原子（CrXY中的X和Y）的种类决定了CrXY是铁磁金属还是半导体。出乎意料的是，这些CrXY材料中的CrBrS单层是一种室温铁磁半导体，居里温度为303 K，并且具有0.06 meV的面外磁各向异性能。此外，在CrTeI中发现了3.10 meV的强Dzyaloshinskii-Moriya相互作用（DMI），其主要由非磁性原子Te（I）而非磁性Cr原子的强自旋轨道耦合诱导产生。此外，利用微磁模拟，在没有外部磁场的情况下，斯格明子可以在CrSeBr中稳定存在。更重要的是，通过控制外部磁场的方向，具有面内磁各向异性的CrSeCl中的双聚物可以转变为斯格明子或铁磁态。我们的工作研究了十四种Janus单层，为DMI、斯格明子和双聚物的材料研究提供了指导。
