# A dressed spin qubit in silicon

## Abstract

Coherent dressing of a quantum two-level system provides access to a new quantum system with improved properties—a different and easily tunable level splitting, faster control and longer coherence times. In our work we investigate the properties of the dressed, donor-bound electron spin in silicon, and assess its potential as a quantum bit in scalable architectures. The two dressed spin-polariton levels constitute a quantum bit that can be coherently driven with an oscillating magnetic field, an oscillating electric field, frequency modulation of the driving field or a simple detuning pulse. We measure coherence times of and , one order of magnitude longer than those of the undressed spin. Furthermore, the use of the dressed states enables coherent coupling of the solid-state spins to electric fields and mechanical oscillations.

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## Acknowledgements

This research was funded by the Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology (project number CE110001027) and the US Army Research Office (W911NF-13-1-0024). We acknowledge support from the Australian National Fabrication Facility and from the laboratory of R. Elliman at the Australian National University for the ion-implantation facilities. The work at Keio was supported by the Japanese Society for the Promotion of Science JSPS KAKEN (S) and the Core-to-Core Program.

## Author information

Authors

### Contributions

A.L., R.K., S.S., J.P.D., J.T.M., A.S.D. and A.M. designed the experiments. A.L. performed the measurements and analysed the results with A.M.'s supervision and R.K.'s and S.S.'s assistance. A.L. and F.A.M. performed the simulations with A.M.'s supervision. D.N.J. and J.C.M. designed and performed the 31P implantation experiments. F.E.H. fabricated the device with A.S.D.'s supervision and R.K.'s and S.F.'s assistance. K.M.I. prepared and supplied the 28Si epilayer wafer. A.L. and A.M. wrote the manuscript, with input from all the co-authors.

### Corresponding authors

Correspondence to Arne Laucht or A. Morello.

## Ethics declarations

### Competing interests

The authors declare no competing financial interests.

## Supplementary information

### Supplementary information

Supplementary information (PDF 386 kb)

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Laucht, A., Kalra, R., Simmons, S. et al. A dressed spin qubit in silicon. Nature Nanotech 12, 61–66 (2017). https://doi.org/10.1038/nnano.2016.178

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