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Germanium Nuclear Spin Coupled to SiMOS Quantum Dots

ORAL

Abstract

Background – With several contenders to realize qubits for quantum computation, SiMOS quantum dots are one of the leading qubit platforms. With their nanoscale size and CMOS compatibility, they possess the promise of being scaled to billions of physical qubits 1. Nuclear spins are often considered a noise source in SiMOS quantum dot qubit platforms, but they can also act as excellent quantum computation platform with extremely high coherence times at the order of many milliseconds 2. Studying nuclear spins, and in particular high-dimensional nuclear spins, as ancillas for quantum computation, will help scale down the size of quantum processors further and also pave the way forward for encoding error-corrected quantum information 3. Nuclear spin qubits/qudits (8-level systems) have been studied as donor-based platforms for quantum computation in silicon 3,4, but high-spin nuclei coupled to quantum dots remain unstudied.

Objectives – To realize quantum computation based on a high spin nucleus, we aim to couple a single 73Ge nucleus to a SiMOS quantum dot, establishing initialization, readout, and coherent control of 73Ge, with the final goal to encode error-corrected quantum information into the 73Ge Hilbert space.

Methods – We have realized qubits at millikelvin and coupled a single quantum dot to a 73Ge nucleus.

Results & Conclusions – We identify the presence of a single 73Ge spin coupling to a single quantum dot by monitoring the Electron Spin Resonance (ESR) frequency for a prolonged time. We detect 10 equally spaced resonance peaks (~300 kHz spacing), that correspond to the 10 levels of the 73Ge Hilbert space. The resolvable hyperfine coupling of ~300 kHz makes it promising to address the 73Ge Hilbert space, as being able to invert the electron spin at a particular frequency constitutes readout of the nuclear spin 2.



1. Taylor, J. M. et al. Nat. Phys. 1, 177–183 (2005).

2. Pla, J. J. et al. Nature 496, 334–338 (2013).

3. Asaad, S. et al. Nature 579, 205–209 (2020).

4. Fernandez De Fuentes, I.et al. Nat. Comms. 15, 1380 (2024).

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Presenters

  • Arne Laucht

    UNSW Sydney, University of New South Wales

Authors

  • Arne Laucht

    UNSW Sydney, University of New South Wales

  • Paul Steinacker

    University of New South Wales

  • Gauri Goenka

    University of New South Wales, Sydney

  • Santiago Serrano

    UNSW, Diraq, University of New South Wales, Sydney

  • Tuomo I Tanttu

    University of New South Wales

  • Tim Botzem

    University of New South Wales

  • Shao Qi Lim

    The University of Melbourne, University of Melbourne

  • Brett C Johnson

    RMIT University, RMIT

  • Fay Hudson

    UNSW, Diraq, University of New South Wales & Diraq, University of New South Wales, University of New South Wales, Sydney

  • Wee Han Lim

    UNSW, Diraq, University of New South Wales, Sydney, University of New South Wales

  • Andre Saraiva

    Diraq

  • Andrew S Dzurak

    University of New South Wales

  • Andrea Morello

    University of New South Wales

  • Chih-Hwan Yang

    UNSW, Diraq, University of New South Wales, Sydney