Twistronic assembly of 2D materials employs the twist angle between adjacent layers as a tuning parameter for designing the electronic and optical properties of van der Waals heterostructures. Here, we study how interlayer hybridization, weak ferroelectric charge transfer between layers, and a piezoelectric response to deformations set the valence and conduction band edges across the moiré supercell in twistronic homobilayers of MoS₂, MoSe₂, WS₂, and WSe₂. We show that, due to the lack of inversion symmetry in the monolayer crystals, bilayers with parallel (P) and antiparallel (AP) unit cell orientations display contrasting behaviors. For P-bilayers at small twist angles, we find band edges in the middle of triangular domains of preferential stacking. In AP-bilayers at marginal twist angles (${\theta }_{AP}<1°$), the band edges are located in small regions around the intersections of domain walls, giving highly localized quantum dot states.

中文翻译：

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过渡金属二硫属化物的扭曲均层中的能带图

二维材料的扭曲组装采用相邻层之间的扭曲角作为设计范德华异质结构的电子和光学特性的调谐参数。在这里，我们研究了层间杂化、层间弱铁电电荷转移以及对变形的压电响应如何在 MoS ₂、MoSe ₂、WS ₂和 WSe _{2 的}扭电子同层中跨越莫尔超晶胞设置价带和导带边缘. 我们表明，由于单层晶体缺乏反转对称性，具有平行 (P) 和反平行 (AP) 晶胞取向的双层显示出对比行为。对于小扭转角的 P 双层，我们在优先堆叠的三角形域的中间发现了带边缘。在边缘扭曲角的 AP 双层中（${\theta }_{\mathrm{一种}磷}<1°$)，带边缘位于畴壁交叉点周围的小区域，提供高度局部化的量子点状态。