Electric-field control of interfacial spin-orbit fields

Current-induced spin-orbit magnetic fields, which arise in single-crystalline ferromagnets with broken inversion symmetry and in non-magnetic metal/ferromagnetic metal bilayers, produce spin-orbit torques that can be used to manipulate the magnetization of a ferromagnet. In single-crystalline Fe/GaAs (001) heterostructures, for example, interfacial spin-orbit magnetic fields emerge at the Fe/GaAs interface due to the lack of inversion symmetry. To develop low-power spin-orbit torque devices, it is important to have electric-field control over such spin-orbit magnetic fields. Here, we show that the current-induced spin-orbit magnetic fields at the Fe/GaAs (001) interface can be controlled with an electric field. In particular, by applying a gate voltage across the Fe/GaAs interface, the interfacial spin-orbit field vector acting on Fe can be robustly modulated via a change in the magnitude of the interfacial spin-orbit interaction. Our results illustrate that the electric field in a Schottky barrier is capable of modifying spin-orbit magnetic fields, an effect that could be used to develop spin-orbit torque devices with low power consumption.