Fast Superdiffusive Transport of Dipolar Excitons in 3R-Stacked MoS2 Bilayers.

Excitons provide opportunities for energy transport without charge flow, but their electrical neutrality limits external control. Creating dipolar excitons, in which electrons and holes are spatially separated, imparts permanent dipole moments that enable electric-field manipulation and introduce strong dipole-dipole interactions that shape transport. While dipolar excitons have been extensively studied in coupled quantum wells and van der Waals heterostructures, here we show that rhombohedral (3R) stacked MoS2 bilayers offer an intrinsic platform for their realization. The broken inversion symmetry of 3R stacking generates a built-in polarization that spatially separates electrons and holes, naturally forming aligned dipoles. Using transient absorption microscopy, we observe rapid and superdiffusive transport of dipolar excitons in 3R MoS2 bilayers, in sharp contrast to the slow and diffusive dynamics in monolayers, bulk crystals, and 2H bilayers. These findings demonstrate how dipolar interactions drive exciton transport and show 3R-stacked transition-metal dichalcogenide bilayers as a material platform for high-mobility exciton transport, tunable optoelectronic functionality, and the exploration of dipole-mediated quantum phases.