Photoexcitation of moiré-trapped interlayer excitons via chiral phonons

Moiré superlattices in transition-metal dichalcogenide semiconductor heterobilayers enable the quantum confinement of interlayer excitons with large out-of-plane permanent electric dipoles and spin-valley control. Here, we report a novel phonon-assisted excitation mechanism of individual moiré-trapped interlayer excitons in 2H-stacked MoSe2/WSe2 heterobilayers via chiral E″ in-plane optical phonons at the Γ-point. This excitation pathway preserves valley-selective optical selection rules and enables deterministic generation of individual interlayer excitons with defined helicity, emitting within a spectrally narrow energy spread. Through photoluminescence excitation spectroscopy in both the ensemble and quantum emitter regimes, we identify a fixed phonon energy of ~23 meV mediating the process. First-principles calculations corroborate the symmetry and energy of the relevant phonon mode and its coupling to interlayer excitons, providing microscopic support for the observed valley-selective phonon-assisted excitation mechanism. Our results highlight the utility of chiral phonons as a tool for controlled excitation of quantum emitters in TMD moiré systems, opening new opportunities for valleytronic and quantum photonic applications.