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Free keywords:
Density functional theory, Electronic structure, Landforms, Magnetic fields, Magnetic moments, Photoelectron spectroscopy, Sulfur compounds, Transition metals, Dichalcogenides, External magnetic field, Global inversion, Inversion asymmetry, Proximity couplings, Spin splittings, Spin-orbit couplings, Stabilizing properties, Surface layers, Transition metal dichalcogenides (TMD), Niobium compounds
Abstract:
Spin–valley locking is ubiquitous among transition metal dichalcogenides with local or global inversion asymmetry, in turn stabilizing properties such as Ising superconductivity, and opening routes towards ‘valleytronics’. The underlying valley–spin splitting is set by spin–orbit coupling but can be tuned via the application of external magnetic fields or through proximity coupling. However, only modest changes have been realized to date. Here, we investigate the electronic structure of the V-intercalated transition metal dichalcogenide V1/3NbS2 using microscopic-area spatially resolved and angle-resolved photoemission spectroscopy. Our measurements and corresponding density functional theory calculations reveal that the bulk magnetic order induces a giant valley-selective Ising coupling exceeding 50 meV in the surface NbS2 layer, equivalent to application of a ~250 T magnetic field. This energy scale is of comparable magnitude to the intrinsic spin–orbit splittings, and indicates how coupling of local magnetic moments to itinerant states of a transition metal dichalcogenide monolayer provides a powerful route to controlling their valley–spin splittings. © 2023, The Author(s), under exclusive licence to Springer Nature Limited.
