Suppression of the D'yakonov-Perel' spin relaxation mechanism for all spin components in [111] zincblende quantum wells

TL;DR

This paper analyzes how spin relaxation in [111] zincblende quantum wells can be suppressed by conditions that eliminate first-order spin splitting, leading to longer spin lifetimes and potential for improved spin storage.

Contribution

It provides analytical expressions for the spin lifetime tensor in [111] QWs and demonstrates conditions for suppressing the D'yakonov-Perel' spin relaxation mechanism.

Findings

Spin splitting vanishes to first order in k under certain conditions.

Suppressed DP spin relaxation leads to extended spin lifetimes.

The spin lifetime tensor depends on BIA and SIA splittings.

Abstract

We apply the D'yakonov-Perel' (DP) formalism to [111]-grown zincblende quantum wells (QWs) to compute the spin lifetimes of electrons in the two-dimensional electron gas. We account for both bulk and structural inversion asymmetry (Rashba) effects. We see that, under certain conditions, the spin splitting vanishes to first order in k, which effectively suppresses the DP spin relaxation mechanism for all spin components. We predict extended spin lifetimes as a result, giving rise to the possibility of enhanced spin storage. We also study [110]-grown QWs, where the effect of structural inversion asymmetry is to augment the spin relaxation rate of the component perpendicular to the well. We derive analytical expressions for the spin lifetime tensor and its proper axes, and see that they are dependent on the relative magnitude of the BIA- and SIA-induced splittings.