Observation and Modulation of High-Temperature Moire-Locale Excitons in van der Waals Heterobilayers

Transition metal dichalcogenide heterobilayers feature strong moire potentials with multiple local minima, which can spatially trap interlayer excitons at different locations within one moire unit cell (dubbed moire locales). However, current studies mainly focus on moire excitons trapped at a single moire locale. Exploring interlayer excitons trapped at different moire locales is highly desirable for building polarized light-emitter arrays and studying multiorbital correlated and topological physics. Here, via enhancing the interlayer coupling and engineering the heterointerface, we report the observation and modulation of high-temperature interlayer excitons trapped at separate moire locales in WS2/WSe2 heterobilayers. These moire-locale excitons are identified by two emission peaks with an energy separation of similar to 60 meV, exhibiting opposite circular polarizations due to their distinct local stacking registries. With the increase of temperature, two momentum-indirect moire-locale excitons are observed, which show a distinct strain dependence with the momentum-direct one. The emission of these moire-locale excitons can be controlled via engineering the heterointerface with different phonon scattering, while their emission energy can be further modulated via strain engineering. Our reported highly tunable interlayer excitons provide important information on understanding moireexcitonic physics, with possible applications in building high-temperature excitonic devices.

Automated summary

Transition metal dichalcogenide heterobilayers exhibit strong moire potentials that can trap interlayer excitons at different locations within one moire unit cell. In this study, high-temperature interlayer excitons trapped at separate moire locales in WS2/WSe2 heterobilayers are observed and modulated. The emission of these excitons can be controlled through engineering the heterointerface with different phonon scattering and the emission energy can be further modulated via strain engineering. These highly tunable interlayer excitons provide valuable insights into moire-exciton physics and have potential applications in high-temperature excitonic devices.