She X C, Zhang R L, Zhao Jin-Zhu, Qi D X, Zou Y, Peng Ru-Wen
National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Phys Chem Chem Phys. 2021 Sep 7;23(33):18182-18188. doi: 10.1039/d1cp02577e. Epub 2021 Aug 16.
We investigate the electronic properties and valley physics of Janus monolayer WSSe on a CrI substrate layer based on first-principles calculations. It is shown that the K and K' valley degeneracy can be lifted which leads to valley polarization (VP) in the WSSe due to the magnetic proximity coupling to a magnetic substrate. The magnitude of VP is highly sensitive to the interfacial electronic properties and can be tuned by varying the stacking configurations of the heterostructure. Interestingly, the direction of VP can be altered by manipulating the layer alignment without reversing the magnetism orientation of the magnetic substrate CrI. We suggest that the hybridization between the bands of WSSe and the substrate plays an important role. Meanwhile, the charge distributions have been mapped out to uncover the microscopic origin of the direction variable VP. In addition, large VP can be achieved by adjusting the interlayer spacing. Our investigations may have potential applications in the design of valleytronic devices.
基于第一性原理计算，我们研究了CrI衬底层上的Janus单层WSSe的电子性质和谷物理。结果表明，由于与磁性衬底的磁近邻耦合，K和K'谷简并可以被消除，从而导致WSSe中的谷极化（VP）。VP的大小对界面电子性质高度敏感，可以通过改变异质结构的堆叠构型来调节。有趣的是，通过操纵层排列可以改变VP的方向，而无需反转磁性衬底CrI的磁取向。我们认为WSSe和衬底的能带之间的杂化起着重要作用。同时，已经绘制出电荷分布以揭示方向可变VP的微观起源。此外，通过调整层间距可以实现大的VP。我们的研究可能在谷电子器件的设计中有潜在应用。
