Moiré effects in vertical stacks of two-dimensional crystals give rise to new quantum materials with rich transport and optical phenomena that originate from modulations of atomic registries within moiré supercells. Due to finite elasticity, however, the superlattices can transform from moiré-type to periodically reconstructed patterns. Here we expand the notion of such nanoscale lattice reconstruction to the mesoscopic scale of laterally extended samples and demonstrate rich consequences in optical studies of excitons in MoSe₂–WSe₂ heterostructures with parallel and antiparallel alignments. Our results provide a unified perspective on moiré excitons in near-commensurate semiconductor heterostructures with small twist angles by identifying domains with exciton properties of distinct effective dimensionality, and establish mesoscopic reconstruction as a compelling feature of real samples and devices with inherent finite size effects and disorder. Generalized to stacks of other two-dimensional materials, this notion of mesoscale domain formation with emergent topological defects and percolation networks will instructively expand the understanding of fundamental electronic, optical and magnetic properties of van der Waals heterostructures.

二维晶体垂直堆叠中的莫尔效应产生了具有丰富传输和光学现象的新型量子材料，这些现象源于莫尔超晶胞内原子登记处的调制。然而，由于弹性有限，超晶格可以从波纹型转变为周期性重建图案。_{在这里，我们将这种纳米级晶格重建的概念扩展到横向扩展样品的介观尺度，并在 MoSe 2} –WSe ₂激子的光学研究中展示了丰富的结果具有平行和反平行排列的异质结构。我们的结果通过识别具有不同有效维数的激子特性的域，为具有小扭曲角的近似相称的半导体异质结构中的莫尔激子提供了一个统一的视角，并将介观重建建立为具有固有有限尺寸效应和无序的真实样品和器件的一个引人注目的特征. 推广到其他二维材料的堆叠，这种具有新兴拓扑缺陷和渗透网络的中尺度域形成的概念将有益地扩展对范德瓦尔斯异质结构的基本电子、光学和磁性特性的理解。