Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 70: Quantum Dots and Wires: Theory
HL 70.4: Vortrag
Donnerstag, 17. März 2011, 11:00–11:15, POT 151
Monitoring the switching of a Mn spin in a quantum dot by optical signals — •Doris E. Reiter1, Vollrath Martin Axt2, and Tilmann Kuhn1 — 1Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster — 2Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth
When a single Mn atom is embedded in a single quantum dot, in the photoluminescence spectrum the exciton line splits into a set of six lines even at zero magnetic field due to the strong exchange interaction between exciton and Mn spin. Each line corresponds to one of the six Mn spin states, such that if the Mn spin is in an eigenstate only a single line with a given spectral position appears. Recently we proposed a protocol to optically switch the Mn spin from a given initial state into all other states using a sequence of laser pulses [PRL 102, 177403 (2009)]. To monitor the dynamics of the Mn spin state we here propose a pump-probe set-up, for which we calculate the optical signals. For the switching steps during the protocol different signatures in the spectrum appear and most remarkably the spectral position of the line in the probe spectrum shifts according to the Mn spin state. With a modified switching protocol superpositions of different Mn spin states can be generated. In the probe spectrum now instead of a single line two lines at the spectral position of the involved Mn spin states show up, while the line strengths correspond to the weights of the superposition. In this contribution we show how the Mn spin dynamics can be deduced from the optical signals.