Optical Spin Orientation in Strained Superlattices

TL;DR

This paper theoretically investigates optical spin orientation in strained semiconductor superlattices, showing how structural parameters influence spin polarization and achieving high polarization levels under certain conditions.

Contribution

It provides a detailed theoretical analysis of how strain and structural parameters affect spin polarization spectra in superlattices, including conditions for polarization exceeding 95%.

Findings

Polarization in the first maximum increases with hh-lh splitting.

Strain and confinement effects significantly influence polarization.

Calculated spectra match experimental polarized electron emission data.

Abstract

Optical orientation in the strained semiconductor superlattices is investigated theoretically. The dependence of the features in spin-polarization spectra on the structure parameters is clarified. The value of polarization in the first polarization maximum in the SL structures is shown to grow with the splitting between the hh- and lh- states of the valence band, the joint strain and confinement effects on the hh1- lh1 splitting being strongly influenced by the tunneling in the barriers. In strained structures with high barriers for the holes initial polarization can exceed 95 %. Calculated polarization spectra are close to the experimental spectra of polarized electron emission.