Spin relaxation in diluted magnetic semiconductor quantum dots

TL;DR

This paper presents a theoretical study of electron spin relaxation in diluted magnetic semiconductor quantum dots, highlighting how various factors influence spin lifetime and relaxation mechanisms.

Contribution

It introduces a comprehensive model including phonon interactions and s-d exchange, revealing detailed dependencies of spin relaxation on material and external parameters.

Findings

Spin lifetime is typically around microseconds.

Spin relaxation increases with Mn concentration and confining strength.

Relaxation is suppressed at high magnetic fields and low Mn concentrations.

Abstract

Electron spin relaxation induced by phonon-mediated s-d exchange interaction in a II-VI diluted magnetic semiconductor quantum dot is investigated theoretically. The electron-acoustic phonon interaction due to piezoelectric coupling and deformation potential is included. The resulting spin lifetime is typically on the order of microseconds. The effectiveness of the phonon-mediated spin-flip mechanism increases with increasing Mn concentration, electron spin splitting, vertical confining strength and lateral diameter, while it shows non-monotonic dependence on the magnetic field and temperature. An interesting finding is that the spin relaxation in a small quantum dot is suppressed for strong magnetic field and low Mn concentration at low temperature.