Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 14: Poster II
HL 14.18: Poster
Monday, March 18, 2024, 15:00–18:00, Poster F
Spin relaxation dynamics of the excited triplet state in self-assembeld quantum dots — •Carl Nelson Creutzburg1, Jens Kerski1, Arne Ludwig2, Andreas D. Wieck2, Martin Geller1, and Axel Lorke1 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen, Germany — 2Chair of Applied Solid State Physics, Ruhr-University Bochum, Germany
The two-electron triplet state in a self-assembled quantum dot can form a spin qubit with the singlet ground state. It is electrically adressable and therefore of interest for quantum information processing. This requires a long coherence time T2, which is limited by the spin relaxation time T1. While T1 has already been investigated by optical measurments, we present our all-electrical measurment approach.
We embedded a layer of InAs/GaAs QDs in an inverted high electron mobility transistor (HEMT) to selectively charge and discharge the QD states with electrons from a tunnel-coupled electron reservoir (2DEG). The 2DEG acts as a sensitive detector for the charge in the QD layer. By using time-resolved transconductance spectroscopy [1] and altering the charging times we can observe the relaxation from the triplet excited state to the singlet ground state. We extract the relaxation time T1 by applying a rate equation model. While there are already first results for T1 [2], ongoing questions of interest are its dependency of the strength and orientation of an external magnetic field.
[1] B. Marquardt. et al., Nature Commun. 2, 209 (2011)
[2] K. Eltrudis. et al., Appl. Phys. Lett. 111, 092103 (2017)
Keywords: Spin relaxation; Transconductance spectroscopy