Tunneling magnetic effect in heterostructures with paramagnetic impurities

TL;DR

This paper presents a theoretical analysis of how paramagnetic impurities near quantum wells influence spin polarization and circularly polarized light emission, explaining experimental results through a hybridization model.

Contribution

It introduces a new theoretical framework based on Anderson-Fano model to describe impurity effects on spin polarization and photoluminescence in heterostructures.

Findings

Resonant enhancement of radiative recombination due to hybridization.

Splitting of localized states causes circular polarization of emitted light.

Model accurately explains experimental photoluminescence spectra.

Abstract

An effect of paramagnetic impurity located in a vicinity of a quantum well (QW) on spin polarization of the carriers in the QW is analyzed theoretically. Within approach of Bardeen's tunneling Hamiltonian the problem is formulated in terms of Anderson-Fano model of configuration interaction between a localized hole state at Mn and continuum of heavy hole states in the InGaAs-based QW. The hybridization between the localized state and the QW leads to resonant enhancement of interband radiative recombination. The splitting of the configuration resonances induced by splitting of the localized state in magnetic field results in circular polarization of light emitted from the QW. The developed theory is capable of explaining known experimental results and allows for calculation of the photoluminescence spectra and dependence of integral polarization on temperature and other parameters.