Progressive suppression of spin relaxation in 2D channels of finite width

TL;DR

This study demonstrates that reducing the width of 2D semiconductor channels can significantly suppress electron spin relaxation, with a crossover to quasi-1D behavior occurring at tens of mean-free paths, enhancing spin coherence.

Contribution

It introduces a numerical model showing how finite channel width influences spin relaxation, revealing a transition from 2D to quasi-1D behavior and potential for spin relaxation suppression.

Findings

Spin relaxation time increases rapidly as channel width decreases.

Crossover from 2D to quasi-1D behavior occurs at tens of mean-free paths.

Wide channels exhibit conventional 2D spin relaxation values.

Abstract

We have investigated spatio-temporal kinetics of electron spin polarization in semiconductor narrow 2D strip and explored the ability to manipulate spin relaxation. Information about spin of the conduction electrons and mechanisms of spin rotation is incorporated into transport Monte Carlo simulation program. A model problem, involving linear-in-k splitting of the conduction band, responsible for the D'yakonov-Perel' mechanism of spin relaxation in the zinc-blende semiconductors and heterostructures, is solved numerically to yield the decay of spin polarization of an ensemble of electrons in the 2D channel of finite width. For very wide channels, a conventional 2D value of spin relaxation is obtained. With decreasing channel width the relaxation time soares rapidly by orders of magnitude. Surprisingly, the cross-over point between 2D and quasi-1D behavior is found to be at tens of electron mean-free paths. Thus, classically wide channels can effectively suppress electron spin relaxation.