Resonant Coupling of a Moiré Exciton to a Phonon in a WSe2/MoSe2 Heterobilayer.

Moiré patterns with an angular mismatch in van der Waals heterostructures are a fascinating platform to engineer optically generated excitonic properties. The moiré pattern can give rise to spatially ordered exciton ensembles, which offer the possibility for coherent quantum emitters and quantum simulation of many-body physics. The intriguing moiré exciton properties are affected by their dynamics and exciton-phonon interaction. Here, we report the moiré exciton and phonon interaction in a twisted WSe2/MoSe2 heterobilayer. By tuning the excitation energy, we realized the selective excitation of the moiré exciton at phonon resonances and the otherwise negligible small absorption. Furthermore, we revealed the relaxation of moiré exciton ensembles between different potential minima via the resonant phonon scattering process. Our findings highlight resonant coupling of a moiré exciton to a phonon and could pave a new way for the exploration of novel quantum phenomena of the moiré exciton.