Proximity-induced magnetic exchange interactions offer a novel approach to manipulate the valley degree of freedom (DOF) in nonmagnetic monolayers without external magnetic fields. Transition metal dichalcogenides (TMDs) serve as an ideal platform for valleytronics research. Here, by introducing a two-dimensional (2D) magnetic substrate, chromium germanium telluride (CrGeTe₃), we demonstrate effective control over the spin and valley properties of CrGeTe₃/MTe₂ (M = Mo, W) van der Waals (vdW) heterostructures. Our first-principles calculations and $$ model Hamiltonian analysis reveal that the magnetic proximity effect (MPE) induces valley splitting and polarization in monolayer MoTe₂ and WTe₂ through the synergistic action of spin-orbit coupling (SOC) and proximity exchange interactions. Further investigation shows that valley splitting in these heterostructures is highly sensitive to the overlap between the atomic projection positions of TMDs and the magnetic Cr atoms, and can be continuously adjusted by varying the magnetization of CrGeTe₃. Additionally, normal strain and experimentally accessible electric fields can effectively modulate the proximity exchange coupling, thus enabling extensive tunability of valley splitting. These controllable manipulations of the valley DOF through external stimuli mark a significant advancement in valleytronics, paving the way for next-generation electronic devices with enhanced performance and novel functionalities.

中文翻译：

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二维 CrGeTe3/MTe2 （M = Mo， W） 范德华异质结构中的磁邻近效应和可调谷分裂


邻近感应磁交换相互作用提供了一种在没有外部磁场的情况下操纵非磁性单层中的谷自由度 （DOF） 的新方法。过渡金属二硫化物 （TMD） 是 valleytronics 研究的理想平台。在这里，通过引入二维 （2D） 磁性衬底碲化铬 （CrGeTe₃），我们展示了对 CrGeTe₃/MTe₂ （M = Mo， W） 范德华 （vdW） 异质结构的自旋和谷特性的有效控制。我们的第一性原理计算和模型哈密顿分析表明，磁邻近效应 （MPE） 通过自旋轨道耦合 （SOC） 和邻近交换相互作用的协同作用，在单层 MoTe₂ 和 WTe₂ 中诱导谷分裂和极化。进一步的研究表明，这些异质结构中的谷分裂对 TMDs 的原子投影位置和磁性 Cr 原子之间的重叠高度敏感，并且可以通过改变 CrGeTe₃ 的磁化强度来连续调节。此外，法向应变和实验可及的电场可以有效地调节邻近交换耦合，从而实现谷分的广泛可调性。这些通过外部刺激对谷 DOF 的可控操作标志着 valleytronics 的重大进步，为具有增强性能和新功能的下一代电子设备铺平了道路。