Single-Particle-Picture Breakdown in laterally weakly confining GaAs Quantum Dots

TL;DR

This paper investigates excitonic states in weakly confined GaAs quantum dots using advanced spectroscopic techniques and theoretical modeling, revealing limitations of the single-particle Zeeman Hamiltonian for g-factor extraction.

Contribution

It provides a detailed experimental and theoretical analysis of excitonic states and g-factors in GaAs quantum dots, highlighting the breakdown of the single-particle approximation.

Findings

Identification of excited states via temperature, polarization, and magnetic field dependence.

Comprehensive analysis of g-factors and diamagnetic coefficients.

Demonstration that the single-particle Zeeman Hamiltonian is unreliable for g-factor determination.

Abstract

We present a detailed investigation of different excitonic states weakly confined in single GaAs/AlGaAs quantum dots obtained by the Al droplet-etching method. For our analysis we make use of temperature-, polarization- and magnetic field-dependent $\mu$-photoluminescence measurements, which allow us to identify different excited states of the quantum dot system. Besides that, we present a comprehensive analysis of g-factors and diamagnetic coefficients of charged and neutral excitonic states in Voigt and Faraday configuration. Supported by theoretical calculations by the Configuration interaction method, we show that the widely used single-particle Zeeman Hamiltonian cannot be used to extract reliable values of the g-factors of the constituent particles from excitonic transition measurements.