Electric-Field Tunable Spin Texture in Dual-Gated HfS2/Graphene van der Waals Heterostructures

Spin–charge interconversion provides the essential link between spin information and electrical signals in spintronic devices. In spin–orbit coupled systems, spin–charge interconversion can contain multiple components associated with different spin-polarization directions, reflecting the underlying spin texture. Tuning this spin texture, therefore, provides a way to control not only the magnitude of spin–charge interconversion but also the balance among its different components. Graphene-based van der Waals heterostructures provide an attractive platform for this purpose because interfacial spin–orbit coupling can host multiple spin–charge interconversion channels that couple to different spin-polarization directions. Here, we demonstrate electric-field control of spin texture in a dual-gated HfS2/graphene van der Waals heterostructure, where independent control of carrier density and vertical electric field allows us to disentangle electrostatic doping from electric field-induced spin–orbit effects. Nonlocal spin precession measurements show that, near zero vertical electric field, spin–charge interconversion is dominated by a spin Hall component with out-of-plane spins. Increasing the vertical electric field enhances additional in-plane spin components with Rashba–Edelstein-like character, including contributions both parallel and perpendicular to the charge current. These results provide experimental evidence that a vertical electric field can reconfigure the effective spin texture and control the corresponding spin–charge interconversion components, demonstrating electrical tunability of spin–orbit functionalities.