Unraveling the Spin-to-Charge\nCurrent Conversion Mechanism\nand Charge Transfer Dynamics at the Interface of Graphene/WS<sub>2</sub> Heterostructures at Room Temperature

We report experimental investigations of spin-to-charge\ncurrent\nconversion and charge transfer (CT) dynamics at the interface of the\ngraphene/WS<sub>2</sub> van der Waals heterostructure. Pure spin current\nwas produced by the spin precession in the microwave-driven ferromagnetic\nresonance of a permalloy film (Py=Ni<sub>81</sub>Fe<sub>19</sub>)\nand injected into the graphene/WS<sub>2</sub> heterostructure through\na spin pumping process. The observed spin-to-charge current conversion\nin the heterostructure is attributed to the inverse Rashba–Edelstein\neffect (IREE) at the graphene/WS<sub>2</sub> interface. Interfacial\nCT dynamics in this heterostructure was investigated based on the\nframework of the core-hole clock (CHC) approach. The results obtained\nfrom spin pumping and CHC studies show that the spin-to-charge current\nconversion and charge transfer processes are more efficient in the\ngraphene/WS<sub>2</sub> heterostructure compared to isolated WS<sub>2</sub> and graphene films. The results show that the presence of\nWS<sub>2</sub> flakes improves the current conversion efficiency.\nThese experimental results are corroborated by density functional\ntheory (DFT) calculations, which reveal (i) Rashba spin–orbit\nsplitting of graphene orbitals and (ii) electronic coupling between\ngraphene and WS<sub>2</sub> orbitals. This study provides valuable\ninsights for optimizing the design and performance of spintronic devices.