Spin-dependent tunneling in semiconductor heterostructures with a magnetic layer

TL;DR

This paper develops a theoretical model explaining how spin-dependent tunneling in ferromagnet-semiconductor heterostructures leads to circularly polarized photoluminescence, matching experimental observations in InGaAs/Mn systems.

Contribution

The paper introduces a theory that explains the origin of circular polarization in PL due to spin-dependent tunneling in hybrid heterostructures with magnetic layers.

Findings

The theory successfully explains experimental time-resolved PL data.

Circular polarization arises from dynamic electron spin polarization.

Spin-dependent leakage onto Mn states causes the observed polarization.

Abstract

We present a theory that describes the appearance of circular polarization of the photoluminescence (PL) in ferromagnet-semiconductor hybrid heterostructures due to spin-dependent tunneling of photoexcited carriers from a quantum well into a magnetic layer. The theory succeeds in explaining the experimental data on time-resolved PL for heterostructures consisting of InGaAs-based quantum well (QW) and a spatially separated Mn $\delta$-layer. We show that the circular polarization of the PL originates from dynamic spin polarization of electrons due to spin-dependent leakage from the QW onto Mn donor states split by the exchange field of the ferromagnetic Mn delta-layer.