Polarized fine structure in the excitation spectrum of a negatively charged quantum dot

TL;DR

This paper investigates the polarized excitation spectrum of negatively charged quantum dots, revealing fine structure caused by electron-hole exchange interactions and quantum dot asymmetry, advancing understanding of spin interactions in quantum dot systems.

Contribution

It presents the first detailed polarization-resolved spectroscopy of the negative trion in single charge tunable quantum dots, highlighting the role of exchange interactions and asymmetry.

Findings

Observation of polarized fine structure in the p-shell resonance

Identification of electron-hole exchange interaction effects

Insights into quantum dot asymmetry influence

Abstract

We report polarized photoluminescence excitation spectroscopy of the negative trion in single charge tunable InAs/GaAs quantum dots. The spectrum exhibits a p-shell resonance with polarized fine structure arising from the direct excitation of the electron spin triplet states. The energy splitting arises from the axially symmetric electron-hole exchange interaction. The magnitude and sign of the polarization are understood from the spin character of the triplet states and a small amount of quantum dot asymmetry, which mixes the wavefunctions through asymmetric e-e and e-h exchange interactions.