Electric-Field Control of Spin-Orbit Torques in WS2/Permalloy Bilayers.

Transition metal dichalcogenides (TMDs) have drawn great attention owing to their potential for electronic, optoelectronic, and spintronic applications. In TMDs/ferromagnetic bilayers, an efficient spin current can be generated by the TMDs to manipulate the magnetic moments in the ferromagnetic layer. In this work, we report on the electric-field modulation of spin-orbit torques (SOTs) in WS2/NiFe bilayers by the spin-torque ferromagnetic resonance technique. It is found that the radio frequency current can induce a spin accumulation at the WS2/NiFe interface because of the interfacial Rashba-Edelstein effect. As a consequence, the SOT ratio between the field-like and antidamping-like torques can be effectively controlled by applying the back-gate voltage in WS2/NiFe bilayers. These results provide a strategy for controlling the SOT by using semiconducting TMDs.