The spontaneous Hall effect driven by the quantum Berry phase (which serves as an internal magnetic flux in momentum space) manifests the topological nature of quasiparticles and can be used to control the information flow, such as spin and valley^1,2. We report a Hall effect of excitons (fundamental composite particles of electrons and holes that dominate optical responses in semiconductors³). By polarization-resolved photoluminescence mapping, we directly observed the Hall effect of excitons in monolayer MoS₂ and valley-selective spatial transport of excitons on a micrometre scale. The Hall angle of excitons is found to be much larger than that of single electrons in monolayer MoS₂ (ref. 4), implying that the quantum transport of the composite particles is significantly affected by their internal structures. The present result not only poses a fundamental problem of the Hall effect in composite particles, but also offers a route to explore exciton-based valleytronics in two-dimensional materials.

由量子贝里相（在动量空间中作为内部磁通量）驱动的自发霍尔效应表现出准粒子的拓扑性质，可用于控制信息流，例如自旋和谷^1,2。我们报告了激子的霍尔效应（电子和空穴的基本复合粒子，这些粒子控制着半导体^3中的光学响应）。通过偏振分辨光致发光图谱，我们直接观察了单层MoS ₂中激子的霍尔效应和激子在微米尺度上的谷选择性空间迁移。发现激子的霍尔角比单层MoS ₂中的单电子大得多（参考文献4），这表明复合颗粒的量子传输受到其内部结构的显着影响。目前的结果不仅构成了复合颗粒中霍尔效应的根本问题，而且为探索二维材料中基于激子的谷电子学提供了一条途径。