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Fabricating van der Waals Heterostructures with Precise Rotational Alignment
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Spin-Valley Depolarization in van der Waals Heterostructures
Shu-Wen Zheng1, Dan Wang2, Hai-Yu Wang1
1State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
The Journal of Physical Chemistry Letters
|June 13, 2022
Summary
We observed spin-valley depolarization in MoS2-WSe2 heterostructures, revealing distinct electron and hole pathways. Hole polarization lifetime was extended in trilayer structures, advancing valleytronics.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Van der Waals heterostructures offer novel avenues for valleytronics.
- Understanding spin-valley dynamics is crucial for developing advanced electronic devices.
Purpose of the Study:
- To simultaneously observe and analyze the spin-valley depolarization processes of electrons and holes in type-II MoS2-WSe2 heterostructures.
- To investigate the factors influencing spin-valley polarization lifetimes in different heterostructure configurations.
Main Methods:
- Valley-resolved broad-band femtosecond pump-probe spectroscopy was employed.
- Comparative studies were conducted on MoS2-WSe2 and MoS2-WS2 heterostructures, including trilayer configurations.
Main Results:
- Distinct spin-valley depolarization pathways were identified for electrons and holes.
- Hole polarization lifetime was significantly prolonged (over three times) in 2MoS2-WSe2 trilayer heterostructures.
- MoS2-WS2 heterostructures exhibited rapid loss of spin-valley polarization due to strong orbital hybridization.
Conclusions:
- The study provides fundamental insights into spin-valley depolarization mechanisms in van der Waals heterostructures.
- Findings facilitate the design of valleytronic devices with extended polarization lifetimes for information storage and transfer.
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