Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon

Abstract

Inversion symmetry breaking and three-fold rotation symmetry grant the valley degree of freedom to the robust exciton in monolayer transition metal dichalcogenides (TMDCs), which can be exploited for valleytronics applications. However, the short lifetime of the exciton significantly constrains the possible applications. In contrast, dark exciton could be long-lived but does not necessarily possess the valley degree of freedom. In this work, we report the identification of the momentum-dark, intervalley exciton in monolayer WSe2 through low-temperature magneto-photoluminescence (PL) spectra. Interestingly, the intervalley exciton is brightened through the emission of a chiral phonon at the corners of the Brillouin zone (K point), and the pseudoangular momentum (PAM) of the phonon is transferred to the emitted photon to preserve the valley information. The chiral phonon energy is determined to be ~ 23 meV, based on the experimentally extracted exchange interaction (~ 7 meV), in excellent agreement with the theoretical expectation of 24.6 meV. The long-lived intervalley exciton with valley degree of freedom adds an exciting quasiparticle for valleytronics, and the coupling between the chiral phonon and intervalley exciton furnishes a venue for valley spin manipulation.

References in corpus (37)

• Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
• Control of valley polarization in monolayer MoS2 by optical helicity
• MoS_2 as an ideal material for valleytronics: valley-selective circular dichroism and valley Hall effect
• Excitons in atomically thin transition metal dichalcogenides
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
• Breaking of valley degeneracy by magnetic field in monolayer MoSe2
• Electronic structures and theoretical modelling of two-dimensional group-VIB transition metal dichalcogenides
• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
• Exciton Radiative Lifetime in Transition Metal Dichalcogenide Monolayers
• Magnetic brightening and control of dark excitons in monolayer WSe2
• Valley contrasting chiral phonons in monolayer hexagonal lattices
• Carrier and polarization dynamics in monolayer MoS2
• Magnetoelectric effects and valley controlled spin quantum gates in transition metal dichalcogenide bilayers
• In-plane Propagation of Light in Transition Metal Dichalcogenide Monolayers: Optical Selection Rules
• Probing dark excitons in atomically thin semiconductors via near-field coupling to surface plasmon polaritons
• Bright excitons in monolayer transition metal dichalcogenides: from Dirac cones to Dirac saddle points
• Exciton Diamagnetic Shifts and Valley Zeeman Effects in Monolayer WS${}_2$ and MoS${}_2$ to 65 Tesla
• Charge-tuneable biexciton complexes in monolayer WSe${}_2$
• Ultrafast Manipulation of Valley Pseudospin
• Revealing the Biexciton and Trion-exciton Complexes in BN Encapsulated WSe2
• Radiative control of dark excitons at room temperature by nano-optical antenna-tip induced Purcell effect
• Neutral and Charged Inter-Valley Biexcitons in Monolayer MoSe${}_2$
• Fine Structure and Lifetime of Dark Excitons in Transition Metal Dichalcogenide Monolayers
• Microsecond Valley Lifetime of Defect-Bound Excitons in Monolayer WSe${}_2$
• Coulomb-bound four- and five-particle valleytronic states in an atomically-thin semiconductor
• Giant Zeeman splitting inducing near-unity valley polarization in van der Waals heterostructures
• Emerging Photoluminescence from the Dark-Exciton Phonon Replica in Monolayer WSe2
• Biexciton fine structure in monolayer transition metal dichalcogenides
• Phonon-derived ultrafast relaxation of spin-valley polarized states in MoS_{2}
• Gate tunable dark trions in monolayer WSe${}_2$
• Long-Lived Valley Polarization of Intra-Valley Trions in Monolayer WSe2
• Zeeman Splitting and Inverted Polarization of Biexciton Emission in Monolayer WS2
• Long valley lifetime of dark excitons in single-layer WSe2
• Zeeman splitting via spin-valley-layer coupling in bilayer MoTe2
• Atomically inspired $k\cdot p$ approach and valley Zeeman effect in transition metal dichalcogenide monolayers
• Observation of Ultralong Valley Lifetime in WSe2/MoS2 Heterostructures

Cited by in corpus (50)

• Large effective magnetic fields from chiral phonons in rare-earth halides
• Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe${}_2$
• Strain control of hybridization between dark and localized excitons in a 2D semiconductor
• Chiral Phonons in Chiral Materials
• Chiral phonons and pseudo-angular momentum in non-symmorphic systems
• Excitonic complexes in $n$-doped WS${}_2$ monolayer
• Intrinsic Donor-Bound Excitons in Ultraclean Monolayer Semiconductors
• 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
• Weyl phonons in chiral crystals
• Neutral and charged dark excitons in monolayer WS${}_2$
• Flipping exciton angular momentum with chiral phonons in MoSe${}_2$/WSe${}_2$ heterobilayers
• Interaction-driven transport of dark excitons in 2D semiconductors with phonon-mediated optical readout
• Chiral valley phonons and flat phonon bands in moiré materials
• Manipulation of Exciton Dynamics in Single-Layer WSe2 Using a Toroidal Dielectric Metasurface
• Vibrational dichroism of chiral valley phonons
• Selective observation of enantiomeric chiral phonons in $\alpha$-quartz
• Up- and Down-Conversion between Intra- and Inter-Valley Excitons in Waveguide Coupled Monolayer WSe2
• Trion photoluminescence and trion stability in atomically thin semiconductors
• Strain-induced activation of chiral-phonon emission in monolayer WS${}_2$
• Electric field-induced nonreciprocal spin current due to chiral phonons in chiral-structure superconductors
• Phonon chirality manipulation mechanism in TMD interlayer-sliding ferroelectrics
• Exciton-activated effective phonon magnetic moment in monolayer MoS2
• Tuning exciton complexes in twisted bilayer WSe2 at intermediate misorientation
• Intervalley electron-hole exchange interaction and impurity-assisted recombination of indirect excitons in WS${}_2$ and WSe${}_2$ monolayers
• Theory of the Coherent Response of Magneto-Excitons and Magneto-Biexcitons in Monolayer Transition Metal Dichalcogenides
• Chiral phonons entangled with multiple Hall effects and unified convention for pseudoangular momentum in 2D materials
• Valley-mediated singlet- and triplet-polaron interactions and quantum dynamics in a doped WSe${}_2$ monolayer
• Raman scattering excitation in monolayers of semiconducting transition metal dichalcogenides
• Electric field control of phonon angular momentum in perovskite BaTiO${}_3$
• Dark exciton energy splitting in monolayer WSe2: insights from time-dependent density-functional theory
• Chiral phonons in binary compounds $A$Bi ($A$ = K, Rb, Cs) with P2${}_1$/c structure
• Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
• Nonexponential photoluminescence dynamics in an inhomogeneous ensemble of excitons in WSe${}_2$ monolayers
• Electrically Controllable Chiral Phonons in Ferroelectric Materials
• Phonon Edelstein effect in chiral metals
• Physics of Phonons in Systems with Approximate Screw Symmetry
• Spin-spin interaction mediated by chiral phonons
• Multidimensional sensing of proximity magnetic fields via intrinsic activation of dark excitons in WSe${}_2$/CrCl${}_3$ heterostructure
• Hybrid dark excitons in monolayer ${MoS}_2$
• Signatures of valley drift in the diversified band dispersions of bright, gray, and dark excitons in MoS2 monolayers under uni-axial strains
• Chiral phonons of honeycomb-type bilayer Wigner crystals
• Extremely high excitonic $g$-factors in 2D crystals by alloy-induced admixing of band states
• Dynamical Orbital Angular Momentum Induced by Circularly Polarized Phonons
• Gate-tunable chiral phonons in low-buckled group-IVA monolayers
• Brightening dark excitons and trions in systems with a Mexican-hat energy dispersion: example of InSe
• Long-lived populations of momentum- and spin-indirect excitons in monolayer WSe${}_2$
• Optical response of WSe${}_2$-based vertical tunneling junction
• Supercurrent-induced phonon angular momentum
• Radiative Decay of Dark Exciton Related Emission in a Sandwiched Monolayer WSe2 Revealed by Room Temperature Micro and Nano Photoluminescence