Dresden 2026 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 17: Quantum Dots and Wires: Rings, Wires and Transport
HL 17.8: Talk
Tuesday, March 10, 2026, 11:30–11:45, POT/0251
Spin relaxation dynamics of the excited triplet state in self-assembeld quantum dots — •Carl Nelson Creutzburg1, 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 self-assembled quantum dots (QDs) can pair with the singlet ground state to form an electrically addressable spin qubit candidate. Using such qubits for quantum information processing requires long coherence times T2, ultimately limited by the spin relaxation time T1. While T1 has predominantly been probed using optical techniques, we here present an all-electrical approach to access the spin relaxation dynamics.
The QDs are embedded in an inverted high-electron-mobility transistor, allowing controlled electron tunneling between the dots and a coupled two-dimensional electron gas (2DEG), which also serves as a sensitive charge detector. Using time-resolved transconductance spectroscopy [1] with a three-level pulse sequence, we observe the relaxation from the excited triplet to the singlet state as a function of the charging interval. A rate-equation analysis yields the spin relaxation time T1. This approach provides an independent and complementary route to previous studies [2] and may help refine key assumptions.
[1] B. Marquardt et al., Nature Commun. 2, 209 (2011)
[2] K. Eltrudis et al., Appl. Phys. Lett. 111, 092103 (2017)
Keywords: self-assembeld quantum dots; transconductance spectroscopy; spin relaxation