Polaron-induced changes in moiré exciton propagation in twisted van der Waals heterostructures.

Twisted transition metal dichalcogenides (TMDs) present an intriguing platform for exploring excitons and their transport properties. By introducing a twist angle, a moiré superlattice forms, providing a spatially dependent exciton energy landscape. Based on a microscopic many-particle theory, we investigate in this work polaron-induced changes in exciton transport properties in the exemplary MoSe2 /WSe2 heterostructure. We demonstrate that polaron formation and the associated enhancement of the moiré exciton mass lead to a significant band flattening. As a result, the moiré inter-cell tunneling and the propagation velocity undergo noticeable temperature and twist-angle dependent changes. We predict a reduction of the hopping strength ranging from 80% at a twist angle of 1° to 30% at 3° at room temperature. The provided microscopic insights into the spatio-temporal exciton dynamics in presence of a moiré potential further expand the possibilities to tune charge and energy transport in 2D materials.