Optical Spectroscopy on Non-Magnetic and Semimagnetic Single Quantum Dots in External Fields

Abstract

We demonstrate the ability to control the eigenstates in single quantum dots by applying well-defined external fields. Electric fields oriented in-plane as well as perpendicular to the disc-shaped dots allow a modification of the spatial part of the excitonic wavefunction, giving access to the charge distribution in the dot. In contrast, magnetic fields modify the spin part of the wavefunction, resulting in a Zeeman splitting and a diamagnetic shift of the photoluminescence emission. We used the unique property of semimagnetic quantum dots to tailor the effective g-factor, i.e. the sensitivity of the eigenstates to external magnetic fields, by about two orders of magnitude simply by varying the Mn concentration in the dots.