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Yoan Léger

Single spin detection in magnetic quantum dots

Published on 24 September 2007

Thesis presented September 24, 2007

Using a micro-spectroscopy setup, we studied II-VI semiconductor quantum dots containing a single magnetic impurity (Mn atom). The emission of these systems is controlled by the interactions between the confined carriers and the Mn spin. The different parameters controlling these interactions were determined by magneto-optical experiments. By analyzing the emission spectrum of some of these magnetic quantum dots, we can detect directly the spin state of the magnetic impurity. The detection conditions are strongly influenced by the dot shape anisotropy or an inhomogeneous distribution of strains in the local environment of the dot. The effects of these phenomena were studied in details. We also studied the magneto-optical properties of the different charged states of magnetic quantum dots. This shows the possibility to control electrically or optically the magnetic anisotropy of nanoscopic magnetic systems. Finally, we began to study the dynamics of these systems. Single spin temporal fluctuations were pointed out by analyzing the statistics of photons emitted by single magnetic quantum dots.

Quantum dot, diluted magnetic semiconductor, single spin, micro-spectroscopy

On-line thesis.