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arXiv · 2202.10781

A steady state approach for studying valley relaxation using optical vortex beam

Aswini Kumar Pattanayak·Pritam Das·Avijit Dhara·Devarshi Chakrabarty·Shreya Paul·Kamal Gurnani·Maruthi Manoj Brundavanam·Sajal Dhara
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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.

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Aswini Kumar Pattanayak, Pritam Das, Avijit Dhara, Devarshi Chakrabarty, Shreya Paul, Kamal Gurnani, Maruthi Manoj Brundavanam, Sajal Dhara. 2022-02-22. A steady state approach for studying valley relaxation using optical vortex beam. https://doi.org/10.1021/acs.nanolett.2c00824

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