The main limitation to the high-fidelity quantum control of spins in semiconductors is the presence of strongly fluctuating fields arising from the nuclear spin bath of the host material. We demonstrate here a substantial improvement in single-qubit gate fidelities for an electron spin qubit bound to a 31P atom in natural silicon, by applying adiabatic inversion instead of narrow-band pulses. We achieve an inversion fidelity of 97%, and we observe signatures in the spin resonance spectra and the spin coherence time that are consistent with the presence of an additional exchange-coupled donor. This work highlights the effectiveness of adiabatic inversion techniques for spin control in fluctuating environments.
@article{arxiv.1312.4647,
title = {High-fidelity adiabatic inversion of a $^{31}\mathrm{P}$ electron spin qubit in natural silicon},
author = {Arne Laucht and Rachpon Kalra and Juha T. Muhonen and Juan P. Dehollain and Fahd A. Mohiyaddin and Fay Hudson and Jeffrey C. McCallum and David N. Jamieson and Andrew S. Dzurak and Andrea Morello},
journal= {arXiv preprint arXiv:1312.4647},
year = {2015}
}