Twist angle dependent interlayer transfer of valley polarization from excitons to free charge carriers in WSe${}_2$/MoSe${}_2$ heterobilayers

Abstract

We identify an optical excitation mechanism that transfers a valley polarization from photo-excited electron-hole pairs to free charge carriers in twisted WSe${}_2$/MoSe${}_2$ heterobilayers. For small twist angles, the valley lifetimes of the charge carriers are surprisingly short, despite the occurrence of interlayer excitons with their presumably long recombination and polarization lifetimes. For large twist angles, we measure an increase in both the valley polarization and its respective lifetime by more than two orders of magnitude. Interestingly, in such heterobilayers we observe an interlayer transfer of valley polarization from the WSe${}_2$ layer into the MoSe${}_2$ layer. This mechanism enables the creation of a photo-induced valley polarization of free charge carriers in MoSe${}_2$, which amplitude scales with the gate-induced charge carrier density. This is in contrast to monolayer MoSe${}_2$, where such a gate-tunable valley polarization cannot be achieved. By combining time-resolved Kerr rotation, photoluminesence and angle-resolved photoemission spectroscopy measurements with first principles calculations, we show that these findings can be explained by twist angle dependent interlayer scattering mechanisms involving the Q- and $\Gamma$-valleys.

arXiv comment21 pages, 10 figures

References in corpus (56)

• Ultrafast Charge Transfer in Atomically Thin MoS2/WS2 Heterostructures
• Excitons in atomically thin transition metal dichalcogenides
• Observation of Long-Lived Interlayer Excitons in Monolayer MoSe2-WSe2 Heterostructures
• Optical Generation of Excitonic Valley Coherence in Monolayer WSe2
• Exciton physics and device application of two-dimensional transition metal dichalcogenide semiconductors
• Electrical control of interlayer exciton dynamics in atomically thin heterostructures
• Moiré superlattice in a MoSe${}_2$/hBN/MoSe${}_2$ heterostructure: from coherent coupling of inter- and intra-layer excitons to correlated Mott-like states of electrons
• Long-lived direct and indirect interlayer excitons in van der Waals heterostructures
• Anomalous Interlayer Exciton Diffusion in Twist-Angle-Dependent Moiré Potentials of WS${}_2$-WSe${}_2$ Heterobilayers
• Long-lived nanosecond spin relaxation and spin coherence of electrons in monolayer MoS_2 and WS_2
• Exciton Valley Dynamics probed by Kerr Rotation in WSe2 Monolayers
• Control of interlayer excitons in two-dimensional van der Waals heterostructures
• Atomic reconstruction and moiré patterns in transition metal dichalcogenide van der Waals heterostructures
• Momentum-space indirect interlayer excitons in transition metal dichalcogenide van der Waals heterostructures
• First-principles method for electron-phonon coupling and electron mobility: Applications to 2D materials
• Double Indirect Interlayer Exciton in a MoSe2/WSe2 van der Waals Heterostructure
• Dipolar interactions between field-tuneable, localized emitters in van der Waals heterostructures
• Twist Angle Dependent Interlayer Exciton Lifetimes in van der Waals Heterostructures
• Phonon Sidebands in Transition Metal Dichalcogenides
• Microsecond Valley Lifetime of Defect-Bound Excitons in Monolayer WSe${}_2$
• Spin-Orbit mediated spin relaxation in monolayer MoS2
• Giant Zeeman splitting inducing near-unity valley polarization in van der Waals heterostructures
• Microsecond dark-exciton valley polarization memory in 2D heterostructures
• Strain-tunable orbital, spin-orbit, and optical properties of monolayer transition-metal dichalcogenides
• Probing the spin-polarized electronic band structure in monolayer transition metal dichalcogenides by optical spectroscopy
• Exciton g-factors of van der Waals heterostructures from first principles calculations
• Inter- and intra-layer excitons in MoS${}_2$/WS${}_2$ and MoSe${}_2$/WSe${}_2$ heterobilayers
• Resolving spin, valley, and moiré quasi-angular momentum of interlayer excitons in WSe2/WS2 heterostructures
• Ab initio calculations of ultra-short carrier dynamics in 2D materials: valley depolarization in single-layer WSe${}_2$
• Interlayer excitons in MoSe${}_2$/WSe${}_2$ heterostructures from first-principles
• Giant spin-splitting and gap renormalization driven by trions in single-layer WS${}_2$/h-BN heterostructures
• Discrete Interactions between a few Interlayer Excitons Trapped at a MoSe${}_2$-WSe${}_2$ Heterointerface
• Exciton Trapping Is Responsible for the Long Apparent Lifetime in Acid-Treated MoS2
• Condensation signatures of photogenerated interlayer excitons in a van der Waals heterostack
• Probing Many-Body Interactions in Monolayer Transition-Metal Dichalcogenides
• Imaging Spin Dynamics in Monolayer WS2 by Time-Resolved Kerr Rotation Microscopy
• Ultrafast charge-transfer dynamics in twisted MoS${}_2$/WSe${}_2$ heterostructures
• Direct determination of momentum resolved electron transfer in the photo-excited MoS2/WS2 van der Waals heterobilayer by TR-ARPES
• Strongly interaction-enhanced valley magnetic response in monolayer WSe2
• Inter-valley dark trion states with spin lifetimes of 150 ns in WSe${}_2$
• Hexcitons and oxcitons in monolayer WSe${}_2$
• Control of the orbital character of indirect excitons in MoS2/WS2 heterobilayers
• Intrinsic Donor-Bound Excitons in Ultraclean Monolayer Semiconductors
• Valley relaxation of resident electrons and holes in a monolayer semiconductor: Dependence on carrier density and the role of substrate-induced disorder
• Exciton landscape in van der Waals heterostructures
• Unveiling valley lifetimes of free charge carriers in monolayer WSe${}_2$
• Spin States Protected from Intrinsic Electron-Phonon-Coupling Reaching 100 ns Lifetime at Room Temperature in MoSe${}_2$
• Spin/valley coupled dynamics of electrons and holes at the ${\text{MoS}}_2-{\text{MoSe}}_2$ interface
• Semiconducting van der Waals Interfaces as Artificial Semiconductors
• Light-matter interaction in van der Waals heterostructures
• Electric Field Tuning of Band Offsets in Transition Metal Dichalcogenides
• 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
• Radially polarized light beams from spin-forbidden dark excitons and trions in monolayer WSe${}_2$
• Ultrafast pseudospin quantum beats in multilayer WSe${}_2$ and MoSe${}_2$
• Spin-valley dynamics in alloy-based transition metal dichalcogenide heterobilayers
• Two-color Kerr microscopy of two-dimensional materials with sub-picosecond time resolution

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