Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 109: Quantum dots and wires: Quantum communication and quantum information science
HL 109.7: Vortrag
Freitag, 20. März 2015, 12:45–13:00, ER 164
Toward long-lived excitonic qubits in deterministic quantum-dot microlenses — •Tobias Heindel1, Alexander Thoma1, Emma Schmidgall2, Liron Gantz2, Ido Schwartz2, Manuel Gschrey1, Peter Schnauber1, Jan-Hindrik Schulze1, André Strittmatter1, Sven Rodt1, David Gershoni2, and Stephan Reitzenstein1 — 1Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, D-10623, Germany — 2Department of Physics, Technion, Haifa 32000, Israel
In recent years the coherent properties of bright exciton (BE) states in self-assembled semiconductor quantum dots (QD) have been explored [1]. However, the use of BEs for quantum information processing tasks is limited due to their relatively short lifetime - set by its radiative recombination rate. On the other hand, dark exciton states have already proven to constitute an extremly long-lived qubit which is optically accesible via specific biexcitonic states [2].
In this work we report on the exploration of such biexcitonic triplet states in single QDs integrated deterministically into microlenses with enhanced photon-extraction efficiency. In contrast to the common spin-singlet biexciton state, the triplet states are constituted of two s-shell electrons and two holes having parallel spins - thus one hole must be located in the p-shell due to Pauli exclusion principle. A detailed analysis of the dynamics of these spin-blockaded biexciton states is presented via polarization resolved photon-crosscorrelation measurements.
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