Optical readout of charge and spin in a self-assembled quantum dot in a strong magnetic field

TL;DR

This paper demonstrates optical methods to read out charge and spin states in a single quantum dot under high magnetic fields, revealing detailed spectral features linked to electron spin configurations.

Contribution

It provides a combined theoretical and experimental analysis of the emission spectrum of a quantum dot in strong magnetic fields, highlighting spin-flip transitions and charge states.

Findings

Observation of spin-flip transitions as emission line discontinuities

Identification of multiplet structures related to electron number and spin

Agreement between calculated and measured spectra up to 23 Tesla

Abstract

We present a theory and experiment demonstrating optical readout of charge and spin in a single InAs/GaAs self-assembled quantum dot. By applying a magnetic field we create the filling factor 2 quantum Hall singlet phase of the charged exciton. Increasing or decreasing the magnetic field leads to electronic spin-flip transitions and increasing spin polarization. The increasing total spin of electrons appears as a manifold of closely spaced emission lines, while spin flips appear as discontinuities of emission lines. The number of multiplets and discontinuities measures the number of carriers and their spin. We present a complete analysis of the emission spectrum of a single quantum dot with N=4 electrons and a single hole, calculated and measured in magnetic fields up to 23 Tesla.