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Trion Valley Coherence in Monolayer Semiconductors
Kai Hao1, Lixiang Xu1, Fengcheng Wu1
1Department of Physics and Center for Complex Quantum Systems, University of Texas at Austin, Austin, TX 78712, USA.
2D Materials
|September 20, 2017
Summary
Researchers explored trion valley coherence in monolayer MoSe2 using ultrafast spectroscopy. They found this quantum coherence lasts for hundreds of femtoseconds, opening new avenues for valleytronics applications.
Area of Science:
- Quantum physics
- Condensed matter physics
- Materials science
Background:
- Valleytronics utilizes electron valley pseudospin for information processing.
- Monolayer transition metal dichalcogenides (TMDs) show promise for valleytronics due to optical control of exciton valley coherence.
- Charged excitons (trions) offer potential advantages over neutral excitons for valley pseudospin control.
Purpose of the Study:
- To investigate and characterize trion valley coherence in monolayer TMDs, which has been experimentally challenging.
- To explore the potential of trions as information carriers in valleytronics.
Main Methods:
- Ultrafast two-dimensional coherent spectroscopy was employed.
- Resonant generation and detection of trion valley coherence in monolayer MoSe2.
Main Results:
- Trion valley coherence was successfully generated and detected in monolayer MoSe2.
- The observed trion valley coherence persisted for a few hundred femtoseconds.
- The mechanisms limiting trion valley coherence were found to differ from those of exciton valley coherence.
Conclusions:
- Trion valley coherence is experimentally accessible and has a measurable lifetime.
- The distinct coherence mechanisms suggest unique control strategies for trion-based valleytronics.
- This work paves the way for utilizing trions in future valleytronic devices.
Keywords:
transition-metal dichalcogenidestrionstwo-dimensional coherent spectroscopyvalley coherenceMore Related Videos
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