Spin-polarized photocurrents in bilayer VS₂: photogalvanic effect with magnetic and polarization light control

Abstract The photogalvanic effect (PGE) plays a critical role in spintronic applications.However, the simultaneous generation of both pure spin current (PSC) and fully spinpolarized current (FSPC) within a single system remains largely unexplored. In this study, we investigate the PGE in bilayer VS₂ using quantum transport simulations, combining the Keldysh nonequilibrium Green's-function formalisms with densityfunctional theory. Bilayer VS₂, with 2H-and 3R-type stackings that break spatial inversion symmetry, exhibits robust photocurrents under linearly polarized light. These photocurrents show a cosine dependence on polarization angles, consistent with the phenomenological theory of PGE. The photocurrent in the antiparallel configuration (APC) is significantly greater than in the parallel configuration (PC), revealing a pronounced spin-valve effect. Notably, PSC is generated in the APC, while FSPC is observed in the PC, with both being controllable by adjusting photon energy and polarization angle. Interestingly, the magnetoresistance ratio (MR) exceeds 90% for most photon energies, reaching as high as 100%, and the perfect spin polarization efficiency achieves 100% in the PC and 8×10 3 in the APC. These findings highlight bilayer VS₂ as a promising material for advanced spintronic devices.