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Published on: November 28, 2017
Ultrafast Moiré-Resolved Spectroscopy of Interlayer-Exciton Thermalization in Twisted WSe_{2}/WS_{2} Heterobilayers
Jinjae Kim1,2, Hyeonho Lee1,2, Claudia Gollner3,4
1Seoul National University, Department of Physics and Astronomy, Seoul 08826, Korea.
Physical Review Letters
|May 11, 2026
Summary
Interlayer excitons (IXs) in moiré heterobilayers thermalize via phonon scattering in about 15 picoseconds. This study reveals how exciton localization influences IX dynamics in WSe2/WS2 systems.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Optics
Background:
- Interlayer excitons (IXs) in transition metal dichalcogenide moiré heterobilayers are key for studying quantum phases.
- Understanding IX thermalization dynamics is crucial but challenging due to weak oscillator strength.
Purpose of the Study:
- Investigate the thermalization dynamics of IXs in R- and H-stacked WSe2/WS2 heterobilayers.
- Probe exciton behavior within moiré superlattices using advanced spectroscopic techniques.
Main Methods:
- Employed moiré-resolved ultrafast spectroscopy.
- Analyzed intralayer exciton states with specific atomic registry and spatial localization.
- Studied both R- and H-stacked WSe2/WS2 heterobilayers.
Main Results:
- Resolved the formation and cooling kinetics of IXs.
- Determined that IX thermalization occurs via phonon-mediated scattering.
- Identified a thermalization timescale of approximately 15 picoseconds.
- Highlighted the influence of exciton localization and site-specific interactions on IX dynamics.
Conclusions:
- Established a spatially sensitive approach for exciton spectroscopy beyond momentum-space limitations.
- Demonstrated the critical role of localized excitons and specific interactions in IX dynamics.
- Provided insights into the fundamental thermalization processes of interlayer excitons in moiré systems.
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