A Steady-State Approach for Studying Valley Relaxation Using an Optical Vortex Beam.
Nano Lett
; 22(12): 4712-4717, 2022 Jun 22.
Article
em En
| MEDLINE
| ID: mdl-35671461
ABSTRACT
Spin-valley coupling in monolayer transition-metal dichalcogenides gives rise to valley polarization and coherence effect, limited by intervalley scattering caused by exciton-phonon, exciton-impurity, and electron-hole exchange interactions (EHEIs). We explore an approach to tune the EHEI by controlling the exciton center of mass momentum (COM) utilizing the photon distribution of higher-order optical vortex beams. By virtue of this, we have observed exciton-COM-dependent valley depolarization and decoherence, which gives us the ability to probe the valley relaxation time scale in a steady-state measurement. Our steady-state technique to probe the valley dynamics can open up a new paradigm to explore the physics of excitons in two-dimensional systems.
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MEDLINE
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En
Revista:
Nano Lett
Ano de publicação:
2022
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Article
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Índia