Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 24: Poster Session II
HL 24.10: Poster
Dienstag, 13. März 2018, 18:30–20:30, Poster F
Spin relaxation in self-assembled quantum dots — •Isabel Oppenberg1, Kevin Eltrudis1, Annika Kurzmann1, Arne Ludwig2, Andreas D. Wieck2, Martin Geller1, and Axel Lorke1 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen, Lotharstr. 1, 47057 Duisburg — 2Chair for Applied Solid State Physics, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany
Self-assembled quantum dots (QDs) are promising candidates for quantum information devices that require a two level system. One possible realization is the excited two-electron spin triplet state and its singlet ground state. We use self-assembled InAs QDs that are embedded in a GaAs/AlGaAs heterostructure (FET). An electron reservoir (2DEG) is coupled to the QDs for controlled charging and sensitive detection of the charge state of the dots. The method we use is time-resolved transconductance spectroscopy with spin-to-charge conversion [1]. By preparation of the excited two-electron triplet states, we can subsequently observe the spin relaxation in electron emission during the discharging process. At zero magnetic field, we observe spin relaxation times of about 25 µs [2].Optical experiments have already shown a very strong magnetic field dependence of the spin relaxation, even for low fields of a few ten mT [3]. Here, we investigate the magnetic field dependence with our all-electrical measurement technique with fields up of 2 T. [1] B. Marquardt. et al., Nature Commun. 2, 209 (2011) [2] K. Eltrudis. et al., Appl. Phys. Lett. 111, 092103 (2017) [3] R. Dahbashi. PRL 112, 156601 (2014)