Two-dimensional van der Waals Janus materials and their heterostructures offer fertile platforms for designing fascinating functionalities. Here, by means of systematic first-principles studies on van der Waals Janus monolayer Cr-based dichalcogenide halides CrYX (Y = S, Se, Te; X = Cl, Br, I), we find that CrSX (X = Cl, Br, I) are the very desirable high T_C ferromagnetic semiconductors with an out-of-plane magnetization. Excitingly, by the benefit of the large magnetic moments on ligand S²⁻ anions, the sought-after large-gap quantum anomalous Hall effect and sizable valley splitting can be achieved through the magnetic proximity effect in van der Waals heterostructures CrSBr/Bi₂Se₃/CrSBr and MoTe₂/CrSBr, respectively. Additionally, we show that large Dzyaloshinskii–Moriya interactions give rise to skyrmion states in CrTeX (X = Cl, Br, I) under external magnetic fields. Our work reveals that two-dimensional Janus magnet Cr-based dichalcogenide halides have appealing multifunctionalities in the applications of topological electronic and valleytronic devices.

二维范德华 Janus 材料及其异质结构为设计迷人的功能提供了丰富的平台。在此，通过对范德华 Janus 单层 Cr 基二硫化物卤化物 Cr YX ( Y  = S, Se, Te; X  = Cl, Br, I) 的系统第一性原理研究，我们发现 CrS X ( X  = Cl , Br, I) 是非常理想的具有平面外磁化的高T _C铁磁半导体。^{令人兴奋的是，得益于配体 S 2-}上的大磁矩通过范德华异质结构 CrSBr/Bi ₂ Se ₃ /CrSBr 和 MoTe ₂ /CrSBr 中的磁邻近效应，可以实现广受欢迎的大能隙量子反常霍尔效应和相当大的谷分裂。 此外，我们表明，在外部磁场下，大的 Dzyaloshinskii-Moriya 相互作用会在 CrTe X ( X = Cl, Br, I) 中产生斯格明子态。我们的工作表明，二维 Janus 磁体 Cr 基二硫化物卤化物在拓扑电子和谷电子器件的应用中具有吸引人的多功能性。