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-1/2 31P and cat-qubits on the spin-7/2 123Sb nuclei. Isoelectronic nuclear spins coupled to gate-defined quantum dots, such as the naturally occurring 29Si 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 and readout of a spin-9/2 73Ge nuclear spin to a gate-defined quantum dot in SiMOS. The 73Ge nucleus was implanted by isotope-selective ion-implantation. We observe the hyperfine interaction (HFI) to the coupled quantum dot electron and are able to tune it from 180 kHz to 350 kHz, through the voltages applied to the lateral gate electrodes. This work lays the foundation for future spin control experiments on the spin-9/2 qudit as well as more advanced experiments such as entanglement distribution between distant nuclear spins or repeated weak measurements.
@article{arxiv.2510.03981,
title = {Coupling a $^{73}$Ge nuclear spin to an electrostatically defined quantum dot},
author = {Paul Steinacker and Gauri Goenka and Rocky Yue Su and Tuomo Tanttu and Wee Han Lim and Santiago Serrano and Tim Botzem and Jesus D. Cifuentes and Shao Qi Lim and Jeffrey C. McCallum and Brett C. Johnson and Fay E. Hudson and Kok Wai Chan and Christopher C. Escott and Andre Saraiva and Chih Hwan Yang and Vincent Mourik and Andrea Morello and Andrew S. Dzurak and Arne Laucht},
journal= {arXiv preprint arXiv:2510.03981},
year = {2025}
}