Ultrafast Manipulation of Valley Pseudospin

Abstract

The coherent manipulation of spin and pseudospin underlies existing and emerging quantum technologies, including NMR, quantum communication, and quantum computation. Valley polarization, associated with the occupancy of degenerate, but quantum mechanically distinct valleys in momentum space, closely resembles spin polarization and has been proposed as a pseudospin carrier for the future quantum electronics. Valley exciton polarization has been created in the transition metal dichalcogenide (TMDC) monolayers using excitation by circularly polarized light and has been detected both optically and electrically. In addition, the existence of coherence in the valley pseudospin has been identified experimentally. The manipulation of such valley coherence has, however, remained out of reach. Here we demonstrate an all-optical control of the valley coherence by means of the pseudomagnetic field associated with the optical Stark effect. Using below-bandgap circularly polarized light, we experimentally rotate the valley exciton pseudospin in monolayer WSe2 on the femtosecond time scale. Both the direction and speed of the rotation can be optically manipulated by tuning the dynamic phase of excitons in opposite valleys. This study completes the generation-manipulation-detection paradigm for valley pseudospin, enabling the platform of excitons in 2D materials for the control of this novel degree of freedom in solids.

arXiv comment9 pages, 4 figures

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Cited by in corpus (84)

• Excitons in atomically thin transition metal dichalcogenides
• Excitonic linewidth approaching the homogeneous limit in MoS2 based van der Waals heterostructures : accessing spin-valley dynamics
• A Silicon-on-Insulator Slab for Topological Valley Transport
• Valley Manipulation by Optically Tuning the Magnetic Proximity Effect in WSe${}_2$/CrI${}_3$ Heterostructures
• Engineering symmetry breaking in two-dimensional layered materials
• Giant Valley Splitting in Monolayer WS2 by Magnetic Proximity Effect
• Revealing the Biexciton and Trion-exciton Complexes in BN Encapsulated WSe2
• Enhanced Light-Matter Interaction in Two-Dimensional Transition Metal Dichalcogenides
• Defect-induced modification of low-lying excitons and valley selectivity in monolayer transition metal dichalcogenides
• Emerging Photoluminescence from the Dark-Exciton Phonon Replica in Monolayer WSe2
• Optical valley Hall effect for highly valley-coherent exciton-polaritons in an atomically thin semiconductor
• On-Chip Chiral Single-Photon Interface: Isolation and Unidirectional Emission
• Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon
• Giant paramagnetism induced valley polarization of electrons in charge-tunable monolayer MoSe2
• Momentum-Resolved View of Electron-Phonon Coupling in Multilayer WSe${}_2$
• Lattice distortion inducing exciton splitting and coherent quantum beating in CsPbI3 perovskite quantum dots
• Valley coherent exciton-polaritons in a monolayer semiconductor
• Direct Observation of Gate Tunable Dark Trions in Monolayer WSe2
• Zeeman splitting via spin-valley-layer coupling in bilayer MoTe2
• Room-temperature coherent optical manipulation of single-hole spins in solution-grown perovskite quantum dots
• Floquet engineering of strongly-driven excitons in monolayer tungsten disulfide
• Valley-dependent Exciton Fine Structure and Autler-Townes Doublets from Berry Phases in Monolayer Molybdenum Diselenide
• Electrotunable artificial molecules based on van der Waals heterostructures
• Theory and Ab Initio Computation of the Anisotropic Light Emission in Monolayer Transition Metal Dichalcogenides
• Dielectrics for Two-Dimensional Transition Metal Dichalcogenide Applications
• Trion Valley Coherence in Monolayer Semiconductors
• Room Temperature Valley Polarization and Coherence in Transition Metal Dichalcogenide-Graphene van der Waals Heterostructures
• Superior valley polarization and coherence of 2s excitons in monolayer WSe2
• Accurate electronic band gaps of two-dimensional materials from the local modified Becke-Johnson potential
• Gate-Controlled Quantum Dots Based on Two-Dimensional Materials
• Intervalley Scattering of Interlayer Excitons in a MoS${}_2$/MoSe${}_2$/MoS${}_2$ Heterostructure in High Magnetic Field
• Valley-selective optical Stark effect probed by Kerr rotation
• Theoretical phase diagram for the room temperature Electron-Hole Liquid in photo-excited quasi-2D monolayer MoS${}_2$
• All-Optical Ultrafast Valley Switching in Two-Dimensional Materials
• Prolonging Valley Polarization Lifetime through Gate-Controlled Exciton-to-Trion Conversion in Monolayer Molybdenum Ditelluride
• Spin/valley coupled dynamics of electrons and holes at the ${\text{MoS}}_2-{\text{MoSe}}_2$ interface
• Spatiotemporal Mapping of Photocurrent in a Monolayer Semiconductor Using a Diamond Quantum Sensor
• Quantum dot behavior in transition metal dichalcogenides nanostructures
• Ultrafast valley-selective coherent optical manipulation with excitons in WSe${}_2$ and MoS${}_2$ monolayers
• Strain control of exciton and trion spin-valley dynamics in monolayer transition metal dichalcogenides
• Valley Polarization-Electric Dipole Interference and Nonlinear Chiral Selection Rules in Monolayer WSe${}_2$
• Valley Degree of Freedom in Two-Dimensional van der Waals Materials
• Spin-Degenerate Regimes for Single Quantum Dots in Transition Metal Dichalcogenide Monolayers
• Quantum-electrodynamical approach to the exciton spectrum in Transition-Metal Dichalcogenides
• Dynamical optical conductivity for gapped $\alpha -{\mathcal{T}}_3$ materials with a curved "flat" band
• Vibrational dichroism of chiral valley phonons
• Observation of ~100% valley-coherent excitons in monolayer MoS2 through giant enhancement of valley coherence time
• Perfect valley filter based on topological phase in disordered $\mathrm{Sb}$ Monolayer Heterostructure
• Disorder Dependent Valley Properties in Monolayer WSe2
• Valley polarized magnetic state in hole-doped mono layers of transition metal dichalcogenides
• Tunable magneto-optical properties in MoS${}_2$ via defect-induced exciton transitions
• Controlling valley splitting and Polarization of dark- and bi-excitons in monolayer WS${}_2$ by a tilted magnetic field
• Coherent Dynamics of Floquet-Bloch States in Monolayer WS2 Reveals Fast Adiabatic Switching
• Band nonlinearity-enabled manipulation of Dirac nodes, Weyl cones, and valleytronics with intense linearly polarized light
• Mapping light-dressed Floquet bands by highly nonlinear optical excitations and valley polarization
• All-optical valley switch and clock of electronic dephasing
• Microscopic theory of cavity-confined monolayer semiconductors: polariton-induced valley relaxation and the prospect of enhancing and controlling the valley pseudospin by chiral strong coupling
• Gap states and valley-spin filtering in transition metal dichalcogenide monolayers
• Expeditious computation of nonlinear optical properties of arbitrary order with native electronic interactions in the time domain
• Optically controlled single-valley exciton doublet states with tunable internal spin structures and spin magnetization generation
• Valley Phenomena in the Candidate Phase Change Material WSe${}_{2(1-x)}$Te${}_{2x}$
• Photonics in Flatland: Challenges and Opportunities for Nanophotonics with 2D Semiconductors
• Magnetically tunable exciton valley coherence in monolayer WS${}_2$ mediated by the electron-hole exchange and exciton-phonon interactions
• Reduced absorption due to defect-localized interlayer excitons in transition metal dichalcogenide-graphene heterostructures
• Layer-dependent optically-induced spin polarization in InSe
• Effects of Floquet Engineering on the Coherent Exciton Dynamics in Monolayer WS${}_2$
• Tunable exciton valley-pseudospin orders in moiré Bose-Hubbard model
• Optical Switching of Moiré Chern Ferromagnet
• Cross-dimensional valley excitons from Förster coupling in arbitrarily twisted stacks of monolayer semiconductors
• Coupled exciton internal and center-of-mass motions in two-dimensional semiconductors by a periodic electrostatic potential
• Valley-polarization and stable triplet exciton formation in 2D lateral heterostrcuture of hBN-kagome and graphene
• Ultrafast all-optical generation of pure spin and valley currents
• Motion of 2D exciton in momentum space leads to pseudospin distribution narrowing on the Bloch Sphere
• Visualization of optical polarization transfer to photoelectron spin vector emitted from the spin-orbit coupled surface state
• Chiral excitonic systems in twisted bilayers from Förster coupling and unconventional excitonic Hall effects
• Topological Optical Pseudospin Injection Beyond Weyl Semimetals
• Dirac's spectrum from Newton laws in graphene
• Quantum valley pseudospin controlled by strain
• Effect of spin-dependent tunneling and intervalley scattering in magnetic-semiconductor van der Waals heterostructures on exciton and trion polarization
• Valley-controlled many-body exciton interactions in monolayer WSe${}_2$ phototransistors
• Experimental valley qubit state tomography and coherence induced uncertainty relations in monolayer WSe${}_2$
• Floquet engineering in the presence of optically excited carriers
• Radiative Decay of Dark Exciton Related Emission in a Sandwiched Monolayer WSe2 Revealed by Room Temperature Micro and Nano Photoluminescence
• Ferroelectric driven exciton and trion modulation in monolayer MoSe2 and WSe2