Issues pertaining to D'yakonov-Perel' spin relaxation in quantum wire channels

TL;DR

This paper analytically investigates the conditions for D'yakonov-Perel' spin relaxation in quantum wire channels, revealing that multi-channel transport and specific spin-orbit interactions are necessary for its existence, and that single-channel transport can eliminate it.

Contribution

It provides a clear analytical framework identifying the necessary conditions for D'yakonov-Perel' spin relaxation in quantum wires, challenging previous multi-channel approaches for spin transistors.

Findings

D'yakonov-Perel' relaxation requires multi-channel transport and both Rashba and Dresselhaus interactions.

Single-channel transport can fully suppress D'yakonov-Perel' relaxation.

Multi-channeled quantum wires are not ideal for spin transistor applications due to relaxation issues.

Abstract

We elucidate the origin and nature of the D'yakonov-Perel' spin relaxation in a quantum wire structure, showing (analytically) that there are three necessary conditions for it to exist: (i) transport must be multi-channeled, (ii) there must be a Rashba spin orbit interaction in the wire, and (iii) there must also be a Dresselhaus spin orbit interaction. Therefore, the only effective way to completely eliminate the D'yakonov-Perel' relaxation in compound semiconductor channels with structural and bulk inversion asymmetry is to ensure strictly single channeled transport. In view of that, recent proposals in the literature that advocate using multi-channeled quantum wires for spin transistors appear ill-advised.