Stacking different two-dimensional crystals into van der Waals heterostructures provides an exciting approach to designing quantum materials that can harness and extend the already fascinating properties of the constituents. Heterobilayers of transition metal dichalcogenides are particularly attractive for low-dimensional semiconductor optics because they host interlayer excitons—with electrons and holes localized in different layers—which inherit valley-contrasting physics from the monolayers and thereby possess various novel and appealing properties compared to other solid-state nanostructures. This Review presents the contemporary experimental and theoretical understanding of these interlayer excitons. We discuss their unique optical properties arising from the underlying valley physics, the strong many-body interactions and electrical control resulting from the electric dipole moment, and the unique effects of a moiré superlattice on the interlayer exciton potential landscape and optical properties.

将不同的二维晶体堆叠到范德华异质结构中提供了一种激动人心的设计量子材料的方法，该材料可以利用和扩展成分的引人入胜的特性。过渡金属二硫化碳的异质双分子层对低维半导体光学特别有吸引力，因为它们拥有层间激子（电子和空穴位于不同的层中），它们从单层继承了与山谷形成鲜明对比的物理性质，因此与其他固体相比具有各种新颖和吸引人的特性态纳米结构。这篇评论介绍了这些层间激子的当代实验和理论理解。我们讨论了由于潜在的山谷物理学而产生的独特光学特性，