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Chirality-Dependent Dynamic Evolution for Trions in Monolayer WS2
Baixu Xiang1,2, Renqi Wang1, Yuzhong Chen2
1State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing,100084, P. R. China.
Nano Letters
|May 24, 2024
Summary
Monolayer tungsten disulfide exhibits temperature-dependent trion dynamics. Chirality-dependent scattering processes influence relaxation pathways, impacting future valleytronic devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Optics
Background:
- Monolayer transition metal dichalcogenides possess valley-dependent excitonic properties crucial for optoelectronics.
- Trions (charged excitons) in these materials have large binding energies and unique valley characteristics.
Purpose of the Study:
- To investigate the chirality-dependent dynamics of trions in monolayer tungsten disulfide encapsulated by hexagonal boron nitride.
- To understand the temperature-dependent relaxation mechanisms governing trion behavior.
Main Methods:
- Utilizing pump-probe ultrafast transient transmission spectroscopy.
- Employing theoretical simulations to complement experimental observations.
- Performing time-resolved valley-contrast measurements.
Main Results:
- Identified a competition between two relaxation channels for trions, influenced by temperature and chirality-dependent scattering.
- Observed that at room temperature, phonon-assisted upconversion dominates, converting trions to excitons within picoseconds.
- Found that at lower temperatures, valley depolarization becomes significant, increasing trion density in the unpumped valley within picoseconds.
Conclusions:
- The study provides comprehensive insights into trion dynamics in two-dimensional materials.
- Understanding these dynamics is essential for advancing the development of novel valleytronic devices.
Keywords:
chiralitymany-body interactiontransient transmission spectroscopytransition metal dichalcogenidestrion dynamicsMore Related Videos
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