Moir\'e Excitons in Van der Waals Heterostructures

TL;DR

This paper provides experimental evidence that moiré superlattices in van der Waals heterostructures can confine interlayer excitons, opening avenues for engineered nanophotonic and quantum devices.

Contribution

It demonstrates the confinement of interlayer excitons by moiré potentials in MoSe2/WSe2 heterobilayers through spectroscopic analysis.

Findings

Observation of multiple interlayer exciton resonances with polarized emission

Temperature-dependent behavior consistent with exciton confinement

Potential for engineering excitonic crystals for nanophotonics

Abstract

In van der Waals (vdW) heterostructures formed by stacking two monolayer semiconductors, lattice mismatch or rotational misalignment introduces an in-plane moir\'e superlattice. While it is widely recognized that a moir\'e superlattice can modulate the electronic band structure and lead to novel transport properties including unconventional superconductivity and insulating behavior driven by correlations, its influence on optical properties has not been investigated experimentally. We present spectroscopic evidence that interlayer excitons are confined by the moir\'e potential in a high-quality MoSe2/WSe2 heterobilayer with small rotational twist. A series of interlayer exciton resonances with either positive or negative circularly polarized emission is observed in photoluminescence, consistent with multiple exciton states confined within the moir\'e potential. The recombination dynamics and temperature dependence of these interlayer exciton resonances are consistent with this interpretation. These results demonstrate the feasibility of engineering artificial excitonic crystals using vdW heterostructures for nanophotonics and quantum information applications.