Anomalously Enhanced Diffusivity of Moiré Excitons via Manipulating the Interplay with Correlated Electrons

In angle-aligned WS₂/WSe₂ heterobilayers, the interplay between excitons and correlated electrons within the moiré superlattice provides an intriguing platform for actively manipulating the exciton dynamics. Utilizing spatially resolved PL imaging, we systematically study the diffusion of interlayer excitons as a function of doping. Our measurements reveal that exciton diffusivity is highly sensitive to electron density, showing a pronounced enhancement as doping increases when carriers are in Fermi liquid states. However, at fractional fillings, where correlated electrons form generalized Wigner crystals, exciton diffusivity is suppressed. Notably, near the Mott insulator state, we observe orders of magnitude increase in exciton diffusivity. The enhanced diffusivity is more pronounced in 0-degree aligned heterobilayers compared to 60-degree aligned ones, due to the unique spatial localization of interlayer excitons associated with stacking types. Our study demonstrates the exciting opportunities of using correlated electrons to control the moiré excitons for exploring quantum phenomena and excitonic devices.