Symmetry and Control of Spin-Scattering Processes in Two-Dimensional Transition Metal Dichalcogenides

Abstract

Transition metal dichalcogenides (TMDs) combine interesting optical and spintronic properties in an atomically-thin material, where the light polarization can be used to control the spin and valley degrees-of-freedom for the development of novel opto-spintronic devices. These promising properties emerge due to their large spin-orbit coupling in combination with their crystal symmetries. Here, we provide simple symmetry arguments in a group-theory approach to unveil the symmetry-allowed spin scattering mechanisms, and indicate how one can use these concepts towards an external control of the spin lifetime. We perform this analysis for both monolayer (inversion asymmetric) and bilayer (inversion symmetric) crystals, indicating the different mechanisms that play a role in these systems. We show that, in monolayer TMDs, electrons and holes transform fundamentally differently -- leading to distinct spin-scattering processes. We find that one of the electronic states in the conduction band is partially protected by time-reversal symmetry, indicating a longer spin lifetime for that state. In bilayer and bulk TMDs, a hidden spin-polarization can exist within each layer despite the presence of global inversion symmetry. We show that this feature enables control of the interlayer spin-flipping scattering processes via an out-of-plane electric field, providing a mechanism for electrical control of the spin lifetime.

arXiv comment9 pages, 3 figures

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Cited by in corpus (7)

• Orbital Hall effect in bilayer transition metal dichalcogenides: From the intra-atomic approximation to the Bloch states orbital magnetic moment approach
• Signatures of electric field and layer separation effects on the spin-valley physics of MoSe${}_2$/WSe${}_2$ heterobilayers: from energy bands to dipolar excitons
• Strain-induced activation of chiral-phonon emission in monolayer WS${}_2$
• Quadrupolar and Dipolar Excitons in Bilayer 2$H$-MoSe${}_2$
• Magnetic field control of light-induced spin accumulation in monolayer MoSe${}_2$
• Hydrogenic Spin-Valley states of the Bromine donor in 2H-MoTe${}_2$
• Light-matter interactions in layered materials and heterostructures: from moiré physics and magneto-optical effects to ultrafast dynamics and hybrid meta-photonics