Interfacial electric field and spin-orbitronic properties of heavy-metal/CoFe bilayers

Spin-orbit coupling (SOC) has become an important ingredient in magnetic storage devices for the realization of electrical control over magnetic dynamics via spin-orbit torque (SOT). An intriguing platform in controlling spin-orbit properties is the interface between a heavy metal (HM) and a CoFe free magnet. In this paper, we investigate the interfacial electric field and spin-orbitronic properties in HM/CoFe (HM = Pd, Ag, Ir, Pt, Au, Ta, and W) bilayers using first-principles calculations. We calculate the interfacial electric field and spin-orbit moments at the interfacial heavy atom and find that orbital magnetic moments in these heavy atoms are nearly proportional to their spin moments. Furthermore, we compare the SOC strength at the interfacial heavy atom with its bulk value and reveal a linear correlation between the variation of SOC strength and the amplitude of the interfacial electric field. Our results suggest that the HM/CoFe interface plays an essential role in tuning the SOC effect and can b...