Spin accumulation and dynamics in inversion-symmetric van der Waals crystals

Abstract

Inversion symmetric materials are forbidden to show an overall spin texture in their band structure in the presence of time-reversal symmetry. However, in van der Waals materials which lack inversion symmetry within a single layer, it has been proposed that a layer-dependent spin texture can arise leading to a coupled spin-layer degree of freedom. Here we use time-resolved Kerr rotation in inversion symmetric WSe${}_2$ and MoSe${}_2$ bulk crystals to study this spin-layer polarization and unveil its dynamics. Our measurements show that the spin-layer relaxation time in WSe${}_2$ is limited by phonon-scattering at high temperatures and that the inter-layer hopping can be tunned by a small in-plane magnetic field at low temperatures, enhancing the relaxation rates. We find a significantly lower lifetime for MoSe${}_2$ which agrees with theoretical expectations of a spin-layer polarization stabilized by the larger spin-orbit coupling in WSe${}_2$.

References in corpus (14)

• Valley polarization in MoS2 monolayers by optical pumping
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• Exciton Valley Dynamics probed by Kerr Rotation in WSe2 Monolayers
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• Spin-orbit torques in NbSe${}_2$/Permalloy bilayers
• Selective probing of hidden spin-polarized states in inversion-symmetric bulk MoS2
• Dark excitons and the elusive valley polarization in transition metal dichalcogenides
• Intervalley scattering in MoS${}_2$ imaged by two-photon photoemission with a high-harmonic probe
• Intrinsic circular polarization in centrosymmetric stacks of transition-metal dichalcogenides
• Inter-valley dark trion states with spin lifetimes of 150 ns in WSe${}_2$
• Valley Dynamics of Excitons in Monolayer Dichalcogenides
• Long-lived spin polarization in n-doped MoSe${}_2$ monolayers
• Group Theory analysis of phonons in two-dimensional Transition Metal Dichalcogenides

Cited by in corpus (12)

• Two-Dimensional Materials for Energy-Efficient Spin-Orbit Torque Devices
• Exciton valley depolarization in monolayer transition-metal dichalcogenides
• Ab initio Ultrafast Spin Dynamics in Solids
• Twist-dependent intra- and interlayer excitons in moire MoSe2 homobilayers
• Symmetry and Control of Spin-Scattering Processes in Two-Dimensional Transition Metal Dichalcogenides
• Impact of indirect transitions on valley polarization in WS${}_2$ and WSe${}_2$
• Revealing Hidden Spin Polarization in Centrosymmetric van der Waals Materials on Ultrafast Timescales
• Ultrafast Hidden Spin Polarization Dynamics of Bright and Dark Excitons in 2H-WSe${}_2$
• Magnetic field control of light-induced spin accumulation in monolayer MoSe${}_2$
• Layer effects on the magnetic textures in magnets with local inversion asymmetry
• Light-matter interactions in layered materials and heterostructures: from moiré physics and magneto-optical effects to ultrafast dynamics and hybrid meta-photonics
• Spin polarization in Lateral two-dimensional Heterostructures