Optoelectronic spin memories of electrons in semiconductors

TL;DR

This paper investigates optically generated electron spins in semiconductors, demonstrating how external magnetic fields influence spin polarization decay and memory times, with saturation effects due to nuclear interactions.

Contribution

It provides experimental insights into spin memory times and their dependence on magnetic field strength in semiconductor materials.

Findings

Spin polarization decays exponentially over time.

Spin memory times increase with magnetic field strength.

Memory times saturate at sub-microsecond levels due to nuclear coupling.

Abstract

We optically generate electron spins in semiconductors and apply an external magnetic field perpendicularly to them. Time-resolved photoluminescence measurements, pumped with a circularly polarized light, are performed to study the spin polarization and spin memory times in the semiconducting host. The measured spin polarization is found to be an exponential decay with the time delay of the probe. It is also found that the spin memory times, extracted from the polarization decays, enhance with the strength of the external magnetic field. However, at higher fields, the memory times get saturated to sub-{\mu}s because of the coupling for interacting electrons with the local nuclear field.