Room-temperature valley coherence in a polaritonic system

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Information Science

Background:

• Valleytronics seeks to control electron/hole valley pseudospin for information processing.
• Monolayer transition metal dichalcogenides are promising for room-temperature valleytronics due to excitons and photon interfacing.
• Achieving room-temperature valley coherence has been a significant challenge.

Purpose of the Study:

• To demonstrate room-temperature valley coherence in valley-polaritons.
• To investigate the role of exciton-cavity coupling in preserving valley degree of freedom (DOF).
• To explore the potential of 2D materials in practical valleytronic devices.

Main Methods:

• Embedding a monolayer of tungsten diselenide within a monolithic dielectric cavity.
• Formation of half-light, half-matter cavity polaritons.
• Utilizing exciton-cavity coupling as a pathway for coherence preservation.

Main Results:

• Demonstrated room-temperature valley coherence of valley-polaritons.
• Identified exciton-cavity coupling as a decoherence-free decay path.
• Showcased the inheritance of valley DOF by cavity polaritons.

Conclusions:

• Room-temperature valley coherence is achievable in valley-polaritons.
• Exciton-cavity coupling is crucial for maintaining valley coherence.
• This work paves the way for practical valleytronic devices.