Electrically tunable valley dynamics in twisted WSe${}_2$/WSe${}_2$ bilayers

Abstract

The twist degree of freedom provides a powerful new tool for engineering the electrical and optical properties of van der Waals heterostructures. Here, we show that the twist angle can be used to control the spin-valley properties of transition metal dichalcogenide bilayers by changing the momentum alignment of the valleys in the two layers. Specifically, we observe that the interlayer excitons in twisted WSe${}_2$/WSe${}_2$ bilayers exhibit a high (>60%) degree of circular polarization (DOCP) and long valley lifetimes (>40 ns) at zero electric and magnetic fields. The valley lifetime can be tuned by more than three orders of magnitude via electrostatic doping, enabling switching of the DOCP from ~80% in the n-doped regime to <5% in the p-doped regime. These results open up new avenues for tunable chiral light-matter interactions, enabling novel device schemes that exploit the valley degree of freedom.

31 pages, 4 figures in main text, 5 figures in supplemental materials

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Cited by in corpus (39)

• Magic in twisted transition metal dichalcogenide bilayers
• Engineering symmetry breaking in two-dimensional layered materials
• Moiré Excitons Correlated with Superlattice Structure in Twisted WSe${}_2$/WSe${}_2$ Homobilayers
• Excitons in mesoscopically reconstructed moiré heterostructures
• Moiré metrology of energy landscapes in van der Waals heterostructures
• Nonequilibrium Lattice Dynamics in Monolayer MoS2
• Multifaceted moiré superlattice physics in twisted WSe${}_2$ bilayers
• Twist-angle engineering of excitonic quantum interference and optical nonlinearities in stacked 2D semiconductors
• Multi-ultraflatbands tunability and effect of spin-orbit coupling in twisted bilayer transition metal dichalcogenides
• Tunable valley and spin splittings in $\mathrm{VS}{\mathrm{i}}_2{\mathrm{N}}_4$ bilayer
• Electrically controlled emission from singlet and triplet exciton species in atomically thin light emitting diodes
• Chirality induced Giant Unidirectional Magnetoresistance in Twisted Bilayer Graphene
• Reconstruction of moiré lattices in twisted transition metal dichalcogenide bilayers
• Stacking-dependent exciton multiplicity in WSe${}_2$ bilayers
• Moiré induced topology and flat bands in twisted bilayer WSe${}_2$: A first-principles study
• Spatially indirect intervalley excitons in bilayer WSe2
• Chiral valley phonons and flat phonon bands in moiré materials
• Chirality of Valley Excitons in Monolayer Transition-Metal Dichalcogenides
• Valley two-qubit system in a MoS${}_2$-monolayer gated double quantum dot
• Flat-band plasmons in twisted bilayer transition metal dichalcogenides
• Leaky exciton condensates in transition metal dichalcogenide moiré bilayers
• Excitonic Absorption Signatures of Twisted Bilayer WSe${}_2$ by Electron Energy-Loss Spectroscopy
• Visualizing giant ferroelectric gating effects in large-scale WSe${}_2$/BiFeO${}_3$ heterostructures
• Switching between Mott-Hubbard and Hund physics in moiré quantum simulators
• Spin-valley dynamics in alloy-based transition metal dichalcogenide heterobilayers
• Tuning exciton complexes in twisted bilayer WSe2 at intermediate misorientation
• Valleytronic full configuration-interaction approach: An application to the excitation spectra of Si double-dot qubits
• Electrically tunable layer-hybridized trions in doped WSe${}_2$ bilayers
• Emergence of flat bands in the quasicrystal limit of boron nitride twisted bilayers
• Two dimensional semiconductors: optical and electronic properties
• Electric-field-tunable intervalley excitons and phonon replicas in bilayer WSe${}_2$
• Atomic relaxation and flat bands in strain-engineered transition metal dichalcogenide bilayer moiré systems
• Strong atomic reconstruction in twisted bilayers of highly flexible InSe: Machine-Learned Interatomic Potential and continuum model approaches
• Valley Gapless Semiconductor: Models and Applications
• Effective K valley Hamiltonian for TMD bilayers under pressure and application to twisted bilayers with pressure-induced topological phase transitions
• Electric field tunable bands in doubly aligned bilayer graphene hBN moire superlattice
• Selective Excitation of Subwavelength Atomic Clouds
• Moire-Engineered Excitonic Landscape and Phonon-Mediated Recombination in Twisted WSe2 Bilayers
• Realization of Nearly Dispersionless Bands with Strong Orbital Anisotropy from Destructive Interference in Twisted Bilayer MoS2