Phenomenological Model of the Edelstein Effects

Abstract

The spin-charge current interconversion based on the direct and inverse Edelstein effects at the interface has attracted much interest due to its potential for high efficiency. However, the physical parameters that define the direct effect (charge-to-spin) and inverse effect (spin-to-charge) had not been clarified. We developed a phenomenological model that connects the direct and inverse Edelstein effects. Our model implies a trade-off relation between the conversion coefficients for the direct and inverse effects. Thus, a large conversion coefficient for the inverse effect does not necessarily bring a large conversion coefficient for the direct effect. Instead of these coefficients, we propose a figure of merit of Edelstein effects, which consists of two factors ; one of them represents the magnitude of the spin-orbit coupling, and the other represents the strength of the hybridization between bulk and interface states. We discuss how to create the interface that exhibits efficient conversion through Edelstein effects.