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Quantum interference between dark-excitons and zone-edged acoustic phonons in few-layer WS2
Qing-Hai Tan1,2,3, Yun-Mei Li4, Jia-Min Lai1,2
1State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China.
Nature Communications
|January 5, 2023
Summary
We observed Fano resonance, a quantum interference, between dark excitons and acoustic phonons in few-layer tungsten disulfide (WS2). This reveals new insights into exciton-phonon interactions in 2D semiconductors.
Area of Science:
- Condensed Matter Physics
- Quantum Mechanics
- Materials Science
Background:
- Fano resonance is a quantum interference phenomenon between continuum and discrete states.
- Exciton-phonon interactions are crucial for understanding the properties of 2D semiconductors.
- Few-layer transition metal dichalcogenides like WS2 exhibit unique electronic and optical properties.
Purpose of the Study:
- To investigate Fano resonance between dark excitons and zone-edged acoustic phonons in few-layer WS2.
- To explore the role of exciton-phonon coupling in quantum interference phenomena.
- To provide new insights into the fundamental physics of 2D materials.
Main Methods:
- Utilized resonant Raman spectroscopy to probe exciton-phonon interactions.
- Analyzed Fano resonance profiles and asymmetry parameter (q) to characterize coupling strengths.
- Studied few-layer WS2 samples with varying layer numbers.
Main Results:
- Observed distinct Fano resonance between dark excitons and M-point acoustic phonons in few-layer WS2.
- Characterized rich Fano resonance behaviors, including constructive (q > 1 or q < -1) and destructive ( |q| << 1) interference.
- Demonstrated the tunability of Fano resonance by varying the number of WS2 layers.
Conclusions:
- Exciton-phonon interactions lead to observable Fano resonance in few-layer WS2.
- The study provides a new platform for exploring quantum interference in 2D materials.
- Understanding these interferences is key to optimizing transport, optical, and thermodynamic properties of 2D semiconductors.
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