Quantum coherence and interference of a single moiré exciton in nano-fabricated twisted semiconductor heterobilayers

Moiré potential acts as periodic quantum confinement for optically generated exciton, generating spatially ordered zero-dimensional quantum system. However, broad emission spectrum arising from inhomogeneity among moiré potential hinders the exploration of the intrinsic properties of moiré exciton. In this study, we have demonstrated a new method to realize the optical observation of quantum coherence and interference of a single moiré exciton in twisted semiconducting heterobilayer beyond the diffraction limit of light. A significant single and sharp photoluminescence peak from a single moiré exciton has been demonstrated after nano-fabrication. We present the longer duration of quantum coherence of a single moiré exciton, which reaches beyond 10 ps and the accelerated decoherence process with elevating temperature and excitation power density. Moreover, the quantum interference has revealed the coupling between moiré excitons in different moiré potential minima. The observed quantum coherence and interference of moiré exciton will facilitate potential application toward quantum technologies based on moiré quantum systems.