Regensburg 2025 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 29: Poster II
HL 29.66: Poster
Dienstag, 18. März 2025, 18:00–20:00, P1
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 (QD) can pair with the singlet ground state to form a spin qubit. This state is electrically addressable, making it a promising candidate for quantum information processing. Achieving this requires a long coherence time (T2), which is limited by the spin relaxation time (T1). While T1 has been previously studied using optical techniques, we employ an all-electrical measurement approach. The dots are embedded in an inverted high electron mobility transistor (HEMT) to selectively charge and discharge their many-particle states with electrons from a tunnel-coupled electron reservoir (2DEG). The 2DEG also acts as a sensitive detector for the charge in the QD layer. By employing time-resolved transconductance spectroscopy [1] and varying the charging intervals, we observe the relaxation process from the excited triplet state to the singlet ground state. Using a rate equation model, we extract the spin relaxation time T1. While there are already first results for T1 [2], an improved temporal resolution provides new insights that could help to refine assumptions in previous studies.
[1] B. Marquardt. et al., Nature Commun. 2, 209 (2011)
[2] K. Eltrudis. et al., Appl. Phys. Lett. 111, 092103 (2017)
Keywords: quantum dot; self-assembled; spin relaxation; transconductance spectroscopy