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Updated: Jan 12, 2026

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Published on: April 12, 2018
Ten-valley excitonic complexes in charge-tunable monolayer WSe2
Alain Dijkstra1,2,3, Amine Ben Mhenni4,5,6, Dinh Van Tuan7
1Walter Schottky Institute, Technical University of Munich, Garching, Germany. Alain.Dijkstra@tum.de.
Researchers discovered a new many-body exciton in tungsten diselenide (WSe2) by filling its K and Q valleys. This finding advances understanding of excitonic complexes and quantum many-body theories in 2D semiconductors.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Excitons are fundamental to the optical properties of 2D semiconductors.
- Strong exciton interactions lead to complex behaviors, crucial for testing theories.
- Understanding these interactions is key to advancing quantum many-body physics.
Purpose of the Study:
- To report the observation of a novel many-body exciton in WSe2.
- To investigate the conditions for the emergence of this exciton.
- To explore its physical properties and theoretical implications.
Main Methods:
- Fabrication of charge-tunable devices with ultra-thin dielectrics for high doping levels.
- Optical probing of the excitonic landscape.
- Magneto-optical measurements to elucidate exciton physics.
Main Results:
- Observation of a new, thermodynamically stable many-body exciton in WSe2 upon filling K and Q valleys.
- High doping levels (up to 10^13 cm^-2) were achieved, enabling exciton formation.
- Experimental results were successfully modeled by considering interacting Fermi seas.
Conclusions:
- The discovered exciton expands the known range of excitonic complexes in 2D materials.
- This complex serves as a platform for probing the limits of exciton models.
- It offers new avenues for studying screened Coulomb interactions in 2D systems.
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