GaN/AlN Quantum Dots for Single Qubit Emitters

TL;DR

This paper theoretically investigates GaN/AlN quantum dots as potential sources of single polarized photons, analyzing their electronic and polarization properties for quantum communication applications.

Contribution

It introduces a detailed theoretical analysis of the polarization control in GaN/AlN quantum dots using eight-band k.p theory and external stress.

Findings

Anisotropy in quantum dots causes strong linear polarization of optical transitions.

External uniaxial stress can induce or compensate polarization effects.

Quantum dots can be engineered for polarized single-photon emission.

Abstract

We study theoretically the electronic properties of $c$-plane GaN/AlN quantum dots (QDs) with focus on their potential as sources of single polarized photons for future quantum communication systems. Within the framework of eight-band k.p theory we calculate the optical interband transitions of the QDs and their polarization properties. We show that an anisotropy of the QD confinement potential in the basal plane (e.g. QD elongation or strain anisotropy) leads to a pronounced linear polarization of the ground state and excited state transitions. An externally applied uniaxial stress can be used to either induce a linear polarization of the ground-state transition for emission of single polarized photons or even to compensate the polarization induced by the structural elongation.