Van der Waals (vdW) heterobilayers formed by two-dimensional (2D) transition metal dichalcogenides (TMDCs) created a promising platform for various electronic and optical properties, ab initio band results indicate that the band offset of type-II band alignment in TMDCs vdW heterobilayer could be tuned by introducing Janus WSSe monolayer, instead of an external electric field. On the basis of symmetry analysis, the allowed interlayer hopping channels of TMDCs vdW heterobilayer were determined, and a four-level k·p model was developed to obtain the interlayer hopping. Results indicate that the interlayer coupling strength could be tuned by interlayer electric polarization featured by various band offsets. Moreover, the difference in the formation mechanism of interlayer valley excitons in different TMDCs vdW heterobilayers with various interlayer hopping strength was also clarified.

由二维（2D）过渡金属双金属双金属卤化物（TMDC）形成的范德华（vdW）异质双分子层为各种电子和光学性质创造了一个有希望的平台，从头算带结果表明，TMDCs vdW中II型能带排列的能带偏移可以通过引入Janus WSSe单层而不是外部电场来调整异质双分子层。在对称性分析的基础上，确定了TMDCs vdW异质双层的允许层间跳跃通道，并确定了四级k·p。开发模型以获得层间跳跃。结果表明，层间耦合强度可以通过具有各种带偏移的层间电极化来调节。此外，还阐明了具有不同层间跳变强度的不同TMDCs vdW异质双层中层间谷底激子形成机理的差异。