Initialization and Readout of Nuclear Spins via a Negatively Charged Silicon-Vacancy Center in Diamond

In this Letter, we demonstrate initialization and readout of nuclear spins via a negatively charged silicon-vacancy (SiV) electron spin qubit. Under Hartmann-Hahn conditions the electron spin polarization is coherently transferred to the nuclear spin. The readout of the nuclear polarization is observed via the fluorescence of the SiV. We also show that the coherence time of the nuclear spin (6 ms) is limited by the electron spin-lattice relaxation due to the hyperfine coupling to the electron spin. This Letter paves the way toward realization of building blocks of quantum hardware with an efficient spin-photon interface based on the SiV color center coupled to a long lasting nuclear memory.

M. H. Metsch, K. Senkalla, B. Tratzmiller, J. Scheuer, M. Kern, J. Achard, A. Tallaire, M. B. Plenio, P. Siyushev, and F. Jelezko.
Phys. Rev. Lett. 122, 190503 (2019) (arxiv here)

Some other recent works from this team:
– Synthesis of Loose Nanodiamonds Containing Nitrogen-Vacancy Centers for Magnetic and Thermal Sensing.
A. Tallaire, O. Brinza, M. De Feudis, A. Ferrier, N. Touati, L. Binet, L. Nicolas, T. Delord, G. Hétet, T. Herzig, S. Pezzagna, P. Goldner, J. Achard
ACS Applied Nano Materials (2019),
– Optimizing synthetic diamond samples for quantum sensing technologies by tuning the growth temperature.
S. Chouaieb, L.J. Martínez, W. Akhtar, I. Robert-Philip, A. Dréau, O. Brinza, J. Achard, A. Tallaire, V. Jacques
Diam. Relat. Mat., 96, pp 85-89 (2019),
– Ohmic graphite-metal contacts on oxygen-terminated lightly boron-doped CVD monocrystalline diamond.
M. De Feudis, V. Mille, A. Valentin, O. Brinza, A. Tallaire, A. Tardieu, R. Issaoui, J. Achard
Diam. Relat. Mat., 92, pp 18-24 (2019),

(a) PLE spectrum of a SiV center at 2 K. The blue-shaded region highlights the zero-phonon line which yields up for 70% of the total fluorescence. The pink region indicates weak phonon sideband. Inset: the physical structure of the defect composed of an interstitial Si atom in between two vacancies. (b) Energy level scheme of a SiV center. Only the lowest Zeeman sublevels in the ground and excited states are shown. c2, c3 denote spin conserving and c1, c4—spin flipping optical transitions. (c) PLE spectrum obtained at 188.7 mT corresponding to the c2 and c3 transitions. The peak separation of 380 MHz corresponds to the difference in Zeeman splitting of the ground and excited states. (d) Polarization of the electron spin of the defect by a laser pulse resonant to the transition c3. Fit to the data yields a polarization of the spin of 92%. Dark blue-shaded areas around the leading and falling edges are integrated and used in all pulsed experiments as measurement and normalization signals, respectively.