Suppression of electron spin relaxation in Mn-doped GaAs

TL;DR

This paper demonstrates significantly extended electron spin relaxation times in Mn-doped GaAs, reaching up to 160 ns, due to antiferromagnetic exchange interactions that suppress spin relaxation mechanisms.

Contribution

It reveals a novel mechanism where antiferromagnetic exchange interactions in Mn-doped GaAs enhance electron spin memory, contrasting with previous understanding of rapid spin relaxation.

Findings

Spin relaxation time increases from 12 ns to 160 ns with optical pumping.

Antiferromagnetic exchange interaction partially compensates fluctuating fields.

Enhanced spin memory is observed in Mn-doped GaAs due to this interaction.

Abstract

We report a surprisingly long spin relaxation time of electrons in Mn-doped p-GaAs. The spin relaxation time scales with the optical pumping and increases from 12 ns in the dark to 160 ns upon saturation. This behavior is associated with the difference in spin relaxation rates of electrons precessing in the fluctuating fields of ionized or neutral Mn acceptors, respectively. For the latter the antiferromagnetic exchange interaction between a Mn ion and a bound hole results in a partial compensation of these fluctuating fields, leading to the enhanced spin memory.