Optoelectronic spin memories of electrons in semiconductors

M Idrish Miah

doi:10.1007/s13204-015-0443-5

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.

Highlights

Spintronics is a relatively new and emerging field in solid-state physics where, rather than the charge of the electron, its spin plays the dominant role
The dynamics of spins generated by an optical technique was studied in the presence of an external magnetic field applied perpendicularly to the spins
The measured spin polarization was found to be an exponential decay with the time delay

Summary

Introduction

Spintronics is a relatively new and emerging field in solid-state physics where, rather than the charge of the electron, its spin plays the dominant role. This has been achieved either by optical method (using a circularly polarized light excitation) or by an electrical means by magnetic semiconductors, or ferromagnetic contacts (Prinz 1998; Awschalom et al 2002). The spin generation by the optical methods has been successful (Prinz 1998) and the high spin polarization of conductor band electrons in semiconductor heterostructures has been obtained (Endo et al 2000).

Results

Conclusion