Optical orientation of Mn^2+ ions in GaAs

TL;DR

This paper demonstrates optical orientation of Mn^2+ ions in GaAs, achieving 25% spin polarization through s-d exchange interaction, and reveals how Mn^2+ stabilizes electron spin dynamics under weak magnetic fields.

Contribution

It provides the first direct measurement of Mn^2+ spin polarization in GaAs using spin flip Raman scattering and explores the interaction between Mn^2+ ions and electron spins.

Findings

Mn^2+ ions achieve 25% spin polarization.

Optically oriented Mn^2+ stabilizes electron spin.

Weak magnetic fields enable optical orientation.

Abstract

We report on optical orientation of Mn^2+ in bulk GaAs under application of weak longitudinal magnetic field (B <= 100 mT). The manganese spin polarization of 25% is directly evaluated using spin flip Raman scattering spectroscopy. The dynamical polarization of Mn^2+ occurs due to s-d exchange interaction with optically oriented conduction band electrons. Time-resolved photoluminescence uncovers nontrivial electron spin dynamics where the oriented Mn^2+ ions tend to stabilize the electron spin.