Spin-Valley Locking Effect in Defect States of Monolayer MoS${}_2$

Abstract

Valley pseudospin in two-dimensional (2D) transition-metal dichalcogenides (TMDs) allows optical control of spin-valley polarization and intervalley quantum coherence. Defect states in TMDs give rise to new exciton features and theoretically exhibit spin-valley polarization; however, experimental achievement of this phenomenon remains challenges. Here, we report unambiguous valley pseudospin of defect-bound localized excitons in CVD-grown monolayer MoS2; enhanced valley Zeeman splitting with an effective g-factor of -6.2 is observed. Our results reveal that all five d-orbitals and the increased effective electron mass contribute to the band shift of defect states, demonstrating a new physics of the magnetic responses of defect-bound localized excitons, strikingly different from that of A excitons. Our work paves the way for the manipulation of the spin-valley degrees of freedom through defects toward valleytronic devices.

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Cited by in corpus (11)

• Valley pseudospin in monolayer MoSi2N4 and MoSi2As4
• Strain-induced semiconductor to metal transition in MA2Z4 bilayers
• Intrinsic Donor-Bound Excitons in Ultraclean Monolayer Semiconductors
• Engineering photonic environments for two-dimensional materials
• Symmetry breaking and spin-orbit coupling for individual vacancy-induced in-gap states in MoS2 monolayers
• Tunable magneto-optical properties in MoS${}_2$ via defect-induced exciton transitions
• Valley polarization and valleyresistance in monolayer transition metal dichalcogenides superlattice
• Valley-resolved Fano resonance in monolayer transition metal dichalcogenides nanoribbons with attached stubs
• Electrostatic control of the trion fine structure in transition metal dichalcogenide monolayers
• Direct observation of ultrafast defect-bound and free exciton dynamics in defect-engineered WS${}_2$ monolayers
• Orbitally resolved single-photon emission from an individual atomic vacancy center in a semiconductor