Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe${}_2$

Abstract

Excitons and trions (or exciton-polarons) in transition metal dichalcogenides (TMDs) are known to decay predominantly through intravalley transitions. Electron-hole recombination across different valleys can also play a significant role in the excitonic dynamics, but intervalley transitions are rarely observed in monolayer TMDs, because they violate the conservation of momentum. Here we reveal the intervalley recombination of dark excitons and trions through more than one path in monolayer WSe${}_2$. We observe the intervalley dark excitons, which can recombine by the assistance of defect scattering or chiral-phonon emission. We also reveal that a trion can decay in two distinct paths - through intravalley or intervalley electron-hole recombination - into two different final valley states. Although these two paths are energy degenerate, we can distinguish them by lifting the valley degeneracy under a magnetic field. In addition, the intra- and inter-valley trion transitions are coupled to zone-center and zone-corner chiral phonons, respectively, to produce distinct phonon replicas. The observed multipath optical decays of dark excitons and trions provide much insight into the internal quantum structure of trions and the complex excitonic interactions with defects and chiral phonons in monolayer valley semiconductors.

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Cited by in corpus (36)

• Guide to optical spectroscopy of layered semiconductors
• Exciton optics, dynamics and transport in atomically thin semiconductors
• Strain control of hybridization between dark and localized excitons in a 2D semiconductor
• Photoluminescence imaging of single photon emitters within nanoscale strain profiles in monolayer WSe${}_2$
• Excitonic complexes in $n$-doped WS${}_2$ monolayer
• Hexcitons and oxcitons in monolayer WSe${}_2$
• Magnetooptics of layered two-dimensional semiconductors and heterostructures: progress and prospects
• Relaxation and darkening of excitonic complexes in electrostatically-doped monolayer semiconductors: Roles of exciton-electron and trion-electron interactions
• Chiral Phonons in Moiré Superlattices
• Neutral and charged dark excitons in monolayer WS${}_2$
• Spatially indirect intervalley excitons in bilayer WSe2
• Up- and Down-Conversion between Intra- and Inter-Valley Excitons in Waveguide Coupled Monolayer WSe2
• Trion photoluminescence and trion stability in atomically thin semiconductors
• Variationally optimized orbital approach to trions in two-dimensional materials
• Charge Density Wave Activated Excitons in TiSe${}_2$-MoSe${}_2$ Heterostructures
• Phonon chirality manipulation mechanism in TMD interlayer-sliding ferroelectrics
• The effect of dielectric environment on the brightening of neutral and charged dark excitons in WSe${}_2$ monolayer
• Exciton-activated effective phonon magnetic moment in monolayer MoS2
• Excitons and trions in monolayer semiconductors with correlated electrons
• Intervalley electron-hole exchange interaction and impurity-assisted recombination of indirect excitons in WS${}_2$ and WSe${}_2$ monolayers
• Excitons and trions in WSSe monolayers
• Analogy and dissimilarity of excitons in monolayer and bilayer of MoSe${}_2$
• Charge-carrier complexes in monolayer semiconductors
• Raman scattering excitation in monolayers of semiconducting transition metal dichalcogenides
• Dark exciton energy splitting in monolayer WSe2: insights from time-dependent density-functional theory
• Two dimensional semiconductors: optical and electronic properties
• Magneto-Optical Measurements of the Negatively Charged 2$s$ Exciton in WSe${}_2$
• Engineering Purcell factor anisotropy for dark and bright excitons in two dimensional semiconductors
• Multidimensional sensing of proximity magnetic fields via intrinsic activation of dark excitons in WSe${}_2$/CrCl${}_3$ heterostructure
• Electric-field-tunable intervalley excitons and phonon replicas in bilayer WSe${}_2$
• Energy shifts and broadening of excitonic resonances in electrostatically-doped semiconductors
• Single charge control of localized excitons in heterostructures with ferroelectric thin films and two-dimensional transition metal dichalcogenides
• Chiral phonons of honeycomb-type bilayer Wigner crystals
• Signatures of valley drift in the diversified band dispersions of bright, gray, and dark excitons in MoS2 monolayers under uni-axial strains
• Extremely high excitonic $g$-factors in 2D crystals by alloy-induced admixing of band states
• Long-lived populations of momentum- and spin-indirect excitons in monolayer WSe${}_2$