Correlation-Driven Ultrafast Exciton Diffusion in Hubbard-Regime Moiré Superlattices

Atomically thin transition metal dichalcogenide heterobilayers represent promising platforms for next-generation optoelectronic devices, wherein interlayer excitons serve as carriers for energy and information transport. At the atomic scale, quantum many-body interactions give rise to rich correlation states that challenge classical transport models. However, direct insights into how these correlation states govern exciton dynamics have been limited by the constraints of conventional electrical measurements. Here, we directly image ultrafast exciton diffusion in WS_{2}/WSe_{2} moiré superlattices and uncover a tunable cascade transport mechanism governed by the interplay between Hubbard interactions and correlated electron states. By independently tuning exciton and carrier populations via optical injection and electrostatic doping, we demonstrate that strong on-site Hubbard interactions can significantly enhance exciton mobility. In contrast, correlated electron phases-such as generalized Wigner crystals-dramatically suppress transport through enhanced exciton-electron scattering. These findings provide a quantum-based strategy for controlling exciton transport, offering a versatile framework for designing reconfigurable excitonic circuits and multifunctional quantum optoelectronic devices.