Regensburg 2022 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 2: Spin Phenomena in Semiconductors

HL 2.3: Vortrag

Montag, 5. September 2022, 10:15–10:30, H31

Selective optical charging and spin preparation of a single quantum dot molecule — •C. Thalacker¹, F. Bopp¹, A. Ahmadi¹, N. Revenga¹, F. Vögl¹, C. Cullip¹, K. Boos¹, F. Sbresny¹, N. Bart², A. Wieck², A. Ludwig², D. Reuter³, J. Schall⁴, S. Reitzenstein⁴, H. Riedl¹, K. Müller¹, and J. J. Finley¹ — ¹Walter Schottky Institut and Physik Department, TU München, Garching, Germany — ²Ruhr-Universität Bochum, Bochum, Germany — ³Universität Paderborn, Paderborn, Germany — ⁴Technische Universität Berlin, Berlin, Germany

Coherence, ease of control and scalability lie at the heart of hardware for distributed quantum technologies. Spin-photon interfaces based on III-V semiconductor quantum dots (QDs) combine properties such as strong light-matter-interactions, robust spin-photon selection rules and ease of integration into opto-electronic devices. Two vertically stacked QDs, a so-called QD-molecule (QDM) are expected to exhibit enhanced coherence times (T₂^*) due to the formation of singlet-triplet (S-T) qubits. We embed a single QDM into an ultralow capacitance p-i-n diode that allows for ultrafast electrical tuning (>500 MHz). Photon extraction efficiencies are improved to >20% by deterministically placing a circular Bragg grating around the QDM. Using our device we demonstrate all optical control of the charge state, as well as optical spin pumping. Our results form the basis of an optically active S-T spin-qubit with enhanced coherence.