Sustainable spin current in the time-dependent Rashba system

TL;DR

This paper demonstrates how time-dependent modulation of Rashba spin-orbit coupling in a 2DEG can generate and control spin currents and polarization, even amidst impurity scattering, using a non-Abelian gauge field approach.

Contribution

It introduces a novel method to generate and manipulate spin currents via time-dependent Rashba SOC modulation, revealing new control mechanisms in spintronics.

Findings

Spin current can be generated with impurity scattering present.

Spin precession is controllable by modulation frequency.

High-frequency modulation suppresses spin precession.

Abstract

The generation of spin current and spin polarization in 2DEG Rashba system is considered, in which the spin-orbital coupling (SOC) is modulated by an ac gate voltage. By using non-Abelian gauge field method, we show the presence of an additional electric field. This field induces a spin current generated even in the presence of impurity scattering and is related to the time-modulation of the Rashba SOC strength. In addition, the spin precession can be controlled by modulating the modulation frequency of the Rashba SOC strength. It is shown that at high modulation frequency, the precessional motion is suppressed so that the electron spin polarization can be sustained in the 2DEG