Decay of spin polarized hot carrier current in a quasi one-dimensional spin valve structure

TL;DR

This paper investigates how spin polarized hot carrier current decays in a quasi-one-dimensional spin valve, revealing longer relaxation lengths due to confinement effects and temperature dependence, with implications for spintronic device design.

Contribution

It demonstrates that one-dimensional confinement significantly extends spin relaxation lengths compared to two-dimensional structures, highlighting the role of Rashba spin orbit interaction and temperature.

Findings

Relaxation length decreases with increasing temperature.

Relaxation length exhibits non-monotonic dependence on electric field.

Relaxation lengths are an order of magnitude larger than in 2D structures.

Abstract

We study the spatial decay of spin polarized hot carrier current in a spin-valve structure consisting of a semiconductor quantum wire flanked by half-metallic ferromagnetic contacts. The current decays because of D'yakonov-Perel' spin relaxation in the semiconductor caused by Rashba spin orbit interaction. The associated relaxation length is found to decrease with increasing lattice temperature (in the range 30-77 K) and exhibit a non-monotonic dependence on the electric field driving the current. The relaxation lengths are several tens of microns which are at least an order of magnitude larger than what has been theoretically calculated for two-dimensional structures at comparable temperatures, Rashba interaction strengths and electric fields. This improvement is a consequence of one-dimensional carrier confinement that does not necessarily suppress carrier scattering, but nevertheless suppresses D'yakonov-Perel' spin relaxation.