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Robust Room Temperature Valley Hall Effect of Interlayer Excitons.
Zumeng Huang1, Yuanda Liu1, Kévin Dini1
1Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 639798 Singapore.
Nano Letters
|January 1, 2020
Summary
Researchers demonstrate the room-temperature valley Hall effect (VHE) in MoS2/WSe2 heterostructures. This robust VHE of interlayer excitons opens possibilities for advanced opto-valleytronic devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Optoelectronics
Background:
- Berry curvature in transition metal dichalcogenides (TMDs) creates a valley-dependent magnetic field, leading to the valley Hall effect (VHE).
- VHE separates carriers/excitons by valley index, crucial for valleytronics, but previously observed only at cryogenic temperatures.
Purpose of the Study:
- To demonstrate the valley Hall effect (VHE) of interlayer excitons in a MoS2/WSe2 heterostructure at room temperature.
- To explore the potential of TMD heterostructures for room-temperature opto-valleytronic applications.
Main Methods:
- Utilized photoluminescence mapping to monitor in-plane propagation of interlayer excitons.
- Conducted theoretical simulations to validate experimental observations.
Main Results:
- Successfully demonstrated the VHE of interlayer excitons in MoS2/WSe2 at room temperature.
- Observed spatial separation of excitons into opposite transverse directions based on their valley index.
- Theoretical simulations accurately reproduced the experimental findings.
Conclusions:
- The robust room-temperature VHE of interlayer excitons in TMD heterostructures is achievable due to their long lifetimes.
- This work paves the way for developing practical opto-valleytronic devices utilizing TMDs.
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