Interlayer Exciton Fine Structure in MoSe₂/WSe₂ Heterostructure

The realization of the valleytronics based on transitional metal dichalcogenides (TMDCs) is hindered by the short lifetime of the exciton. Recently, it is predicted that the long-lived interlayer exciton in aligned TMDC hetero-bilayer possesses fine structures with distinctive valley polarization selection rules, which can be utilized to lift this limitation. However, the revealing of the details of the interlayer exciton is hindered by the sample quality. Further, the Moiré effect due to small twist angle also complicates the spectroscopy signature of the interlayer exciton. In this work, we present a comprehensive study of the interlayer excitons through gate-dependent, magnetic-field dependent spectroscopy study. The valley polarization is investigated through photoexcitation spectroscopy (PLE) study, and the high valley polarization of interlayer exciton is also explored. Our work paves the way for future exploration and understanding of the fascinating interlayer excitonic physics and Moiré physics in TMDC heterostructures.