Spin Polarization driven by Itinerant Orbital Angular Momentum in van der Waals Heterostructures

Abstract: We report on the possibility of manipulating magnetic materials by using itinerant orbital angular momentum to produce out-of-plane spin polarization in van der Waals heterostructures. Employing a real-space formulation of the OAM operator within linear response theory, we demonstrate that in low-symmetry transition-metal dichalcogenide (TMD) monolayers, such as 1$T{}_d$-MoTe2, the current-induced itinerant OAM exceeds the spin response by three orders of magnitude. When TMDs are coupled with ferromagnets with negligible intrinsic orbital responses, the itinerant OAM generated by the orbital Rashba-Edelstein effect transfers across the interface, generating spin densities capable of inducing magnetization dynamics inside the ferromagnet. Our findings highlight the previously overlooked role of itinerant OAM in the generation of out-of-plane spin densities, which serves as an emerging mechanism for efficient electrical control of magnetization in low-power, ultracompact storage devices.