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High-lying valley-polarized trions in 2D semiconductors
Kai-Qiang Lin1, Jonas D Ziegler2, Marina A Semina3
1Department of Physics, University of Regensburg, 93053, Regensburg, Germany. kaiqiang.lin@ur.de.
Nature Communications
|November 15, 2022
Summary
Researchers discovered new UV-emissive quasiparticles called high-lying trions in monolayer transition-metal dichalcogenide (TMDC) transistors. Electrical gates can control their quantum interference, opening new possibilities for optoelectronic devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Optics
Background:
- Monolayer transition-metal dichalcogenide (TMDC) semiconductors exhibit tunable optoelectronic properties due to strong Coulomb interactions.
- Manipulation of many-body states in TMDCs has been primarily limited to energies near the fundamental bandgap.
Purpose of the Study:
- To report the observation of novel, tightly bound, valley-polarized, UV-emissive trions in monolayer TMDC transistors.
- To investigate the unique optical properties and electrical tunability of these high-lying trions.
Main Methods:
- Fabrication and characterization of monolayer TMDC transistors.
- Spectroscopic analysis to observe UV emission and excitonic transitions.
- Electrical gating to control trion properties.
Main Results:
- Observation of UV-emissive trions composed of a high-lying conduction band electron, a valence band hole, and a band-edge charge.
- These high-lying trions exhibit distinct optical selection rules and opposite helicity compared to band-edge trions.
- Electrical gate control over oscillator strength and detuning of excitonic transitions, influencing Rabi frequency.
Conclusions:
- Demonstration of deterministic switching of excitonic quantum interference in a driven three-level system.
- These findings expand the accessible energy landscape for tunable many-body states in TMDCs.
- Potential for new applications in optoelectronics and quantum information processing.
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