Polarization analysis of excitons in monolayer and bilayer transition-metal dichalcogenides

Abstract

The polarization analysis of optical transitions in monolayer and bilayer transition-metal dichalcogenides provides invaluable information on the spin and valley (pseudospin) degrees of freedom. To explain optical properties of a given monolayer transition-metal dichalcogenide, one should consider (i) the order of its spin-split conduction bands, (ii) whether intervalley scattering is prone to phonon bottleneck, (iii) and whether valley mixing by electron-hole exchange can take place. Using these principles, we present a consistent physical picture that elucidates a variety of features in the optical spectra of these materials. We explain the differences between optical transitions in monolayer MoSe${}_2$ and monolayer WSe${}_2$, finding that indirect excitons in the latter correspond to several low-energy optical transitions that so far were attributed to excitons bound to impurities. A possible mechanism that can explain the vanishing polarization in MoSe${}_2$ is discussed. Finally, we consider the effect of an out-of-plane electric field, showing that it can reduce the initial polarization of bright excitons due to a Rashba-type coupling with dark excitons.

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• Exciton and trion dynamics in atomically thin MoSe2 and WSe2: effect of localization
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• Magnetic Proximity Effects in Transition-Metal Dichalcogenides: Converting Excitons
• Exciton-phonon coupling in MoSe2 monolayers
• Long-Lived Valley Polarization of Intra-Valley Trions in Monolayer WSe2
• Discrete quantum dot like emitters in monolayer MoSe2: Spatial mapping, Magneto-optics and Charge tuning
• The role of momentum-dark excitons in the elementary optical response of bilayer WSe${}_2$
• Coherent and Incoherent Coupling Dynamics between Neutral and Charged Excitons in Monolayer MoSe2
• Valley-selective chiral phonon replicas of dark excitons and trions in monolayer WSe2
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• Long valley lifetime of dark excitons in single-layer WSe2
• Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe${}_2$
• Exciton states in monolayer MoSe2: impact on interband transitions
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• Probing and manipulating valley coherence of dark excitons in monolayer WSe${}_2$
• Ultrafast dynamics in monolayer TMDCs: the interplay of dark excitons, phonons and intervalley Coulomb exchange
• Probing Many-Body Interactions in Monolayer Transition-Metal Dichalcogenides
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• Marrying excitons and plasmons in monolayer transition-metal dichalcogenides
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• Measurement of Conduction and Valence Bands g-factors in a Transition Metal Dichalcogenide Monolayer
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• Inter-valley dark trion states with spin lifetimes of 150 ns in WSe${}_2$
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• Intrinsic Donor-Bound Excitons in Ultraclean Monolayer Semiconductors
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• Near-field relaxation of a quantum emitter to 2D semiconductors: surface dissipation and exciton polaritons
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• Quenching of Intervalley Exchange Coupling in the Presence of Momentum-Dark States in TMDCs
• Spin/valley coupled dynamics of electrons and holes at the ${\text{MoS}}_2-{\text{MoSe}}_2$ interface
• Interaction-driven transport of dark excitons in 2D semiconductors with phonon-mediated optical readout
• Exciton-phonon relaxation bottleneck and radiative decay of thermal exciton reservoir in two-dimensional materials
• Phonon-assisted exciton and trion conversion efficiency in transition metal Dichalcogenides
• Valley Dynamics of Excitons in Monolayer Dichalcogenides
• Breakdown of Raman Selection Rules By Fröhlich Interaction in Few-Layer WS${}_2$
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• Signatures of electric field and layer separation effects on the spin-valley physics of MoSe${}_2$/WSe${}_2$ heterobilayers: from energy bands to dipolar excitons
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• Chiral excitonic systems in twisted bilayers from Förster coupling and unconventional excitonic Hall effects
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