Logo image
Accuracy of circular polarization as a measure of spin polarization in quantum dot qubits
Journal article   Peer reviewed

Accuracy of circular polarization as a measure of spin polarization in quantum dot qubits

C E Pryor and M E Flatté
Physical review letters, Vol.91(25), pp.257901-2579014
12/19/2003
DOI: 10.1103/PhysRevLett.91.257901
PMID: 14754157
url
https://arxiv.org/pdf/cond-mat/0305304View
Open Access

Abstract

A quantum dot spin light emitting diode provides a test of carrier spin injection into a qubit and a means for analyzing carrier spin injection and local spin polarization. Even with 100% spin-polarized carriers the emitted light may be only partially circularly polarized due to the geometry of the dot. We have calculated carrier polarization-dependent optical matrix elements for InAs/GaAs self-assembled quantum dots (SAQDs) for electron and hole spin injection into a range of quantum dot sizes and shapes, and for arbitrary emission directions. Calculations for typical SAQD geometries with emission along [110] show light that is only 5% circularly polarized for spin states that are 100% polarized along [110]. Measuring along the growth direction gives near unity conversion of spin to photon polarization and is the least sensitive to uncertainties in SAQD geometry.

Details

Metrics

Logo image