Excitonic transport driven by repulsive dipolar interaction in a van der Waals heterostructure

Dipolar bosonic gases are currently the focus of intensive research due to their interesting many-body physics in the quantum regime. Their experimental embodiments range from Rydberg atoms to GaAs double quantum wells and van der Waals heterostructures built from transition metal dichalcogenides. Although quantum gases are very dilute, mutual interactions between particles could lead to exotic many-body phenomena such as Bose-Einstein condensation and high-temperature superfluidity. Here, we report the effect of repulsive dipolar interactions on the dynamics of interlayer excitons in the dilute regime. We image the temporal evolution of an exciton cloud in a van der Waals heterotrilayer, allowing us to reveal repulsive exciton-exciton interactions as the driving force behind exciton transport. This enables direct estimation of the exciton mobility. The presence of interactions significantly modifies the diffusive transport of excitons, effectively enhancing the diffusion coefficient by one order of magnitude. The repulsive dipolar interactions combined with the electrical control of interlayer excitons open up appealing new perspectives for excitonic devices.