Nuclear spins in the solid state are both a cause of decoherence and a valuable resource for spin qubits. In this work, we demonstrate control of isolated 29Si nuclear spins in silicon carbide (SiC) to create an entangled state between an optically active divacancy spin and a strongly coupled nuclear register. We then show how isotopic engineering of SiC unlocks control of single weakly coupled nuclear spins and present an ab initio method to predict the optimal isotopic fraction which maximizes the number of usable nuclear memories. We bolster these results by reporting high-fidelity electron spin control (F=99.984(1)%), alongside extended coherence times (T2=2.3 ms, T2DD>14.5 ms), and a >40 fold increase in dephasing time (T2*) from isotopic purification. Overall, this work underlines the importance of controlling the nuclear environment in solid-state systems and provides milestone demonstrations that link single photon emitters with nuclear memories in an industrially scalable material.
@article{arxiv.2005.07602,
title = {Entanglement and control of single quantum memories in isotopically engineered silicon carbide},
author = {Alexandre Bourassa and Christopher P. Anderson and Kevin C. Miao and Mykyta Onizhuk and He Ma and Alexander L. Crook and Hiroshi Abe and Jawad Ul-Hassan and Takeshi Ohshima and Nguyen T. Son and Giulia Galli and David D. Awschalom},
journal= {arXiv preprint arXiv:2005.07602},
year = {2020}
}