Ultrafast manipulation and quantum kinetics of spin decoherence in magnetic quantum dots

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The main objective of the project is a microscopic theoretical analysis of the ultrafast optical manipulation of spin states in magnetic quantum dot structures including the relevant relaxation and decoherence processes. In the first period we have analyzed the light-induced dynamics in an uncharged CdTe quantum dot doped with a single Mn atom. We have found that by using specific sequences of ultrashort laser pulses the spin of the Mn atom can be driven into each of its six possible orientations. Based on this successful demonstration of an optical control of the Mn spin in a quantum dot, in the following period we are planning to extend our investigations in three directions: (i) we will extend the microscopic theoretical model of the quantum dot structure in order to analyze more quantitatively features which might influence the efficiency of the spin switching dynamics; (ii) new switching protocols will be developed either to optimize the switching of the Mn spin into a specific orientation or to drive the Mn spin into well-defined quantum-mechanical superposition states; (iii) the calculations will be extended to charged quantum dot structures as well as to quantum dot structures made from different material classes, which are again doped with a single (or maybe a few) magnetic atoms.