A steady state approach for studying valley relaxation using optical vortex beam
arXiv:2202.10781 · doi:10.1021/acs.nanolett.2c00824
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 interaction (EHEI). We explore an approach to tune the EHEI by controlling excitons center of mass momentum (COM) utilizing the photon distribution of higher-order optical vortex beam. By virtue of this, we have observed excitons COM-dependent valley depolarization and decoherence which gives us the ability to measure the timescale associated with valley dynamics in the 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.
arXiv comment25 pages, 5 Manuscript figures, 7 Supplementary figures
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- Photonics in Flatland: Challenges and Opportunities for Nanophotonics with 2D Semiconductors
- Formation of dark excitons in monolayer transition metal dichalcogenides by a vortex beam: optical selection rules
- Probing spin dynamics of 2D excitons with twisted light
- Zero-Threshold PT-Symmetric Polariton-Raman Laser