Optical two-dimensional coherent spectroscopy of excitons in transition-metal dichalcogenides

Exciton physics in atomically thin transition-metal dichalcogenides (TMDCs) holds paramount importance for fundamental physics research and prospective applications. However, the experimental exploration of exciton physics, including excitonic coherence dynamics, exciton many-body interactions, and their optical properties, faces challenges stemming from factors such as spatial heterogeneity and intricate many-body effects. In this perspective, we elaborate upon how optical two-dimensional coherent spectroscopy (2DCS) emerges as an effective tool to tackle the challenges, and outline potential directions for gaining deeper insights into exciton physics in forthcoming experiments with the advancements in 2DCS techniques and new materials.