Relaxation and coherent oscillations in the spin dynamics of II-VI diluted magnetic quantum wells

TL;DR

This paper theoretically investigates the ultrafast spin dynamics in II-VI diluted magnetic quantum wells, focusing on the interplay between spin-orbit interaction and exchange coupling, revealing how their competition affects electronic spin oscillations.

Contribution

It extends previous models by incorporating electronic correlations and analyzes how tunable Rashba spin-orbit coupling influences spin dynamics in specific quantum well materials.

Findings

Spin oscillations depend qualitatively on the relative strength of spin-orbit and exchange interactions.

The dependence of spin dynamics on excess energy varies with the dominance of spin-orbit coupling.

Electronic correlations from exchange sd-coupling significantly affect the spin behavior.

Abstract

We study theoretically the ultrafast spin dynamics of II-VI diluted magnetic quantum wells in the presence of spin-orbit interaction. We extend a recent study where it was shown that the spin-orbit interaction and the exchange sd coupling in bulk and quantum wells can compete resulting in qualitatively new dynamics when they act simultaneously. We concentrate on Hg$_{1-x-y}$Mn$_x$Cd$_y$Te quantum wells, which have a highly tunable Rashba spin-orbit coupling. Our calculations use a recently developed formalism which incorporates electronic correlations originating from the exchange $sd$-coupling. We find that the dependence of electronic spin oscillations on the excess energy changes qualitatively depending on whether or not the spin-orbit interaction dominates or is of comparable strength with the sd interaction.