Interface disorder as a cause for kinetic Rashba-Edelstein effect and interface Spin-Hall effect at the metal-insulator boundary

TL;DR

This paper reveals that interface disorder at metal-insulator boundaries can induce extended spin phenomena, including a kinetic Rashba-Edelstein effect and an interface spin-Hall effect, which are significant for spintronic device performance.

Contribution

It introduces the concept of disorder-induced spin effects at interfaces, expanding understanding beyond traditional Rashba-Edelstein and spin-Hall effects.

Findings

Skew scattering causes large-scale spin accumulation.

Interface spin-Hall effect persists within the Born approximation.

Disorder effects can dominate spin phenomena in intermediate-thickness devices.

Abstract

The spin phenomena observed at a clean metall-insulator interface are typically reduced to Rashba-Edelstein effect, that leads to spin accumulation over a few monolayers. We demonstrate that the presence of interface disorder significantly expands the range of potential phenomena. Specifically, the skew scattering at the metal - insulator boundary gives rise to the "kinetic Rashba-Edelstein effect", where spin accumulation occurs on a much larger length scale comparable to mean free path. Moreover, at higher orders of spin-orbit interaction, skew scattering is accompanied with spin relaxation resulting in the interface spin-Hall effect - a conversion of electrical current to spin current at the metal surface. Unlike the conventional spin-Hall effect, this phenomenon persists even within the Born approximation. These two predicted phenomena can dominate the spin density and spin current in devices of intermediate thickness.