Key role of the moiré potential for the quasicondensation of interlayer excitons in van der Waals heterostructures

Transition metal dichalcogenides (TMD) bilayers offer a new platform to study Bose-Einstein condensation of excitons and its related superfluidity. Here, it is shown that such collective quantum phenomena are possibly accessed below around 10 K when a high-$k$ dielectric spacer separates the two TMD monolayers. Without this spacer, interlayer excitons explore a deep moir\'e potential and their effective mass is increased by orders of magnitude, so that quantum statistics plays no role under experimentally accessible conditions.