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

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Barcan, R. A. and Samaras, I. and Barr, K. and Juska, G. and Pelucchi, E. and Lagoudakis, K. G. (2025) Optical pumping and initialization of a hole spin in site-controlled InGaAs pyramidal quantum dots. Physical Review B: Condensed Matter and Materials Physics, 112 (12). L121301. ISSN 1098-0121 (https://doi.org/10.1103/fps4-vb8c)

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Abstract

We characterize site-controlled In₀.₂₅Ga₀.₇₅As quantum dots in (111)B GaAs pyramidal recesses as a platform for spin qubit implementation. 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 5T 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-Λ (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.

ORCID iDs

Barcan, R. A., Samaras, I., Barr, K. ORCID logoORCID: https://orcid.org/0000-0001-6141-4424, Juska, G., Pelucchi, E. and Lagoudakis, K. G. ORCID logoORCID: https://orcid.org/0000-0002-4410-4755;
  • Item type:Article
    ID code:93786
    Dates:
    Date
    Event
    2 September 2025
    Published
    8 August 2025
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:11 Aug 2025 14:37
    Last modified:10 Aug 2026 07:03
    URI:https://strathprints.strath.ac.uk/id/eprint/93786
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