Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2

Abstract

A monolayer of a transition metal dichalcogenide (TMD) such as WSe${}_2$ is a two-dimensional (2D) direct band-gap valley-semiconductor having an effective Honeycomb lattice structure with broken inversion symmetry. The inequivalent valleys in the Brillouin zone could be selectively addressed using circularly-polarized light fields, suggesting the possibility for magneto-optical measurement and manipulation of the valley pseudospin degree of freedom. Here we report such experiments that demonstrate the valley Zeeman effect -- strongly anisotropic lifting of the degeneracy of the valley pseudospin degree of freedom using an external magnetic field. While the valley-splitting measured using the exciton transition is consistent with the difference of the conduction and valence band orbital magnetic moments, the trion transition exhibits an unexpectedly large valley Zeeman effect which cannot be understood using an independent electron-hole picture. Instead, we find an explanation using the recently predicted large Berry curvature and the associated magnetic moment for the electron-hole exchange interaction modified trion dispersion. Our results raise the possibility of observing optical excitation induced valley Hall effect in monolayer TMDs or topological states of photons strongly coupled to trion excitations in a microcavity.

References in corpus (11)

• Two Dimensional Atomic Crystals
• Valley polarization in MoS2 monolayers by optical pumping
• The Valley Hall Effect in MoS2 Transistors
• Tightly bound excitons in monolayer WSe2
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
• Orbital magnetization in periodic insulators
• Robust optical emission polarization in MoS2 monolayers through selective valley excitation

Cited by in corpus (55)

• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
• Exciton band structure of monolayer MoS2
• Ultrafast Generation of Pseudo-magnetic Field for Valley Excitons in WSe2 Monolayers
• Topological Polaritons
• Ultrafast Manipulation of Valley Pseudospin
• Probing the influence of dielectric environment on excitons in monolayer WSe2: Insight from high magnetic fields
• Valley-spin polarized Landau levels in a monolayer semiconductor
• Valley Phonons and Exciton Complexes in a Monolayer Semiconductor
• Exciton and trion dynamics in atomically thin MoSe2 and WSe2: effect of localization
• Valley Polarization by Spin Injection in a Light-Emitting van der Waals Heterojunction
• High quality-factor mechanical resonators based on WSe2 monolayers
• Emerging Photoluminescence from the Dark-Exciton Phonon Replica in Monolayer WSe2
• Magneto-optics in transition metal diselenide monolayers
• Probing the spin-polarized electronic band structure in monolayer transition metal dichalcogenides by optical spectroscopy
• Gate tunable dark trions in monolayer WSe${}_2$
• Optical investigation of monolayer and bulk tungsten diselenide (WSe${}_2$) in high magnetic fields
• Excitonic valley effects in monolayer WS${}_2$ under high magnetic fields
• Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon
• Optical spectroscopy of excited exciton states in MoS2 monolayers in van der Waals heterostructures
• Diffusion quantum Monte Carlo study of excitonic complexes in two-dimensional transition-metal dichalcogenides
• Giant Valley-Zeeman Splitting from Spin-Singlet and Spin-Triplet Interlayer Excitons in WSe2/MoSe2 Heterostructure
• Optospintronics in graphene via proximity coupling
• Valley Zeeman effect and spin-valley polarized conductance in monolayer MoS${}_2$ in a perpendicular magnetic field
• Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe${}_2$
• Identifying defect-related quantum emitters in monolayer WSe${}_2$
• Magneto-photoluminescence of exciton Rydberg states in monolayer WSe${}_2$
• Excitons and trions in monolayer transition metal dichalcogenides: A comparative study between the multiband model and the quadratic single-band model
• Observation of intervalley biexcitonic optical Stark effect in monolayer WS2
• Opto-valleytronic imaging of atomically thin semiconductors
• Luminescent emission of excited Rydberg excitons from monolayer WSe2
• Odd-integer quantum Hall states and giant spin susceptibility in p-type few-layer WSe2
• Giant proximity exchange and valley splitting in transition metal dichalcogenide/$h\mathrm{BN}$/(Co, Ni) heterostructures
• Magneto-optical transport properties of monolayer WSe2
• Landau-quantized excitonic absorption and luminescence in a monolayer valley semiconductor
• Layer degree of freedom for excitons in transition metal dichalcogenides
• Symmetry-forbidden intervalley scattering by atomic defects in monolayer transition-metal dichalcogenides
• Niobium doping induced mirror twin boundaries in MBE grown WSe2 monolayers
• Magneto-spectroscopy of exciton Rydberg states in a CVD grown WSe2 monolayer
• Observation of Ultralong Valley Lifetime in WSe2/MoS2 Heterostructures
• Controlling valley splitting and Polarization of dark- and bi-excitons in monolayer WS${}_2$ by a tilted magnetic field
• Layer and orbital interference effects in photoemission from transition metal dichalcogenides
• Spectrum of exciton states in monolayer transition metal dichalcogenides: angular momentum and Landau levels
• Probing valley filtering effect by Andreev reflection in zigzag graphene nanoribbon
• Revealing the nature of excitons in liquid exfoliated monolayer WS2
• Excitonic magneto-optics in monolayer transition metal dichalcogenides: From nanoribbons to two-dimensional response
• Magneto photoluminescence measurements of tungsten disulphide monolayers
• Theory of the Coherent Response of Magneto-Excitons and Magneto-Biexcitons in Monolayer Transition Metal Dichalcogenides
• Orbital-dependent quasiparticle scattering interference in 3R-NbS2
• Large photoluminescence enhancement by an out-of-plane magnetic field in exfoliated WS${}_2$ flakes
• Non-degenerate valleys in the half-metallic ferromagnet Fe/WS${}_2$
• Asymmetric Andreev resonant state with a magnetic exchange field in spin-triplet superconducting monolayer $Mo{S}_2$
• Single Quantum Emitters in Monolayer Semiconductors
• Single photon emitters in exfoliated WSe2 structures