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arXiv · 2503.05400

Optical pumping and initialization of a hole spin in site-controlled InGaAs pyramidal quantum dots

R. A. Barcan·I. Samaras·K. Barr·G. Juska·E. Pelucchi·K. G. Lagoudakis
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Abstract

We investigate site-controlled In$_{0.25}$Ga$_{0.75}$As quantum dots in (111)B GaAs pyramidal recesses as spin qubits. Combining scanning confocal cryomicroscopy, magneto-photoluminescence studies and resonant excitation, we identify and isolate a positively charged exciton with a hole-spin in its ground state. Application of a strong 5 T magnetic field parallel to the growth axis, induces a fourfold splitting of the energy levels of the positively charged exciton creating an optically addressable double-lambda system. We combine weak above-band and resonant excitation to demonstrate spin pumping and high-fidelity spin initialization through all four optical transitions and study the system behavior as a function of the resonant driving strength showing the existence of a robust spin that can be optically pumped and initialized. These results demonstrate the potential of these quantum dots for precise spin manipulation and their relevance for future quantum hardware.

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R. A. Barcan, I. Samaras, K. Barr, G. Juska, E. Pelucchi, K. G. Lagoudakis. 2025-03-07. Optical pumping and initialization of a hole spin in site-controlled InGaAs pyramidal quantum dots. https://doi.org/10.1103/fps4-vb8c

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