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Coupling a Ge73 Nuclear Spin to an Electrostatically Defined Quantum Dot in Silicon

Paul Steinacker1,2,*, Gauri Goenka1, Rocky Yue Su1, Tuomo Tanttu1,2, Wee Han Lim1,2, Santiago Serrano1,2, Tim Botzem1,2, Jesus D. Cifuentes1,2, Shao Qi Lim3 et al.

Jeffrey C. McCallum4, Brett C. Johnson3, Fay E. Hudson1,2, Kok Wai Chan1,2, Christopher C. Escott2, Andre Saraiva2, Chih Hwan Yang1,2, Vincent Mourik5, Andrea Morello1, Andrew S. Dzurak1,2, and Arne Laucht1,2,†

  • *Contact author: p.steinacker@unsw.edu.au
  • †Contact author: a.laucht@unsw.edu.au
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Phys. Rev. Lett. 136, 230602 – Published 9 June, 2026

DOI: https://doi.org/10.1103/49gt-msw9

Abstract

Single nuclear spins in silicon are a promising resource for quantum technologies due to their long coherence times and excellent control fidelities. Qubits and qudits have been encoded on donor nuclei, with successful demonstrations of Bell states and quantum memories on the spin-/21 P31 and cat-qubits on the spin-/27 Sb123 nuclei. Isoelectronic nuclear spins coupled to gate-defined quantum dots, such as the naturally occurring Si29 isotope, possess no additional charge and allow for the coupled electron to be shuttled without destroying the nuclear spin coherence. Here, we demonstrate the coupling of a spin-/29 Ge73 nuclear spin to a gate-defined quantum dot in SiMOS via Pauli spin blockade readout using rf reflectometry. We observe the hyperfine interaction (HFI) to the coupled quantum dot electron and are able to tune it from 180 to 350 kHz, through the voltages applied to the lateral gate electrodes. This smaller HFI combined with the faster readout enable easier quantum nondemolition readout of the nuclear spin state. Thus, this work lays the foundation for future spin control experiments on the spin-/29 qudit as well as more advanced experiments such as entanglement distribution between distant nuclear spins or repeated weak measurements.

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Phys. Rev. Lett. 136, 230602– Published 9 June, 2026
  • Received 6 October 2025
  • Revised 27 January 2026
  • Accepted 5 May 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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