High-fidelity spin and optical control of single silicon-vacancy centres in silicon carbide.

Nagy, Roland; Niethammer, Matthias; Widmann, Matthias; Chen, Yu-Chen; Udvarhelyi, Péter; Bonato, Cristian; Hassan, Jawad Ul; Karhu, Robin et al. · Nat Commun · 2019

basic_science · Level V

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Abstract

Scalable quantum networking requires quantum systems with quantum processing capabilities. Solid state spin systems with reliable spin-optical interfaces are a leading hardware in this regard. However, available systems suffer from large electron-phonon interaction or fast spin dephasing. Here, we demonstrate that the negatively charged silicon-vacancy centre in silicon carbide is immune to both drawbacks. Thanks to its <sup>4</sup>A<sub>2</sub> symmetry in ground and excited states, optical resonances are stable with near-Fourier-transform-limited linewidths, allowing exploitation of the spin selectivity of the optical transitions. In combination with millisecond-long spin coherence times originating from the high-purity crystal, we demonstrate high-fidelity optical initialization and coherent spin control, which we exploit to show coherent coupling to single nuclear spins with ∼1 kHz resolution. The summary of our findings makes this defect a prime candidate for realising memory-assisted quantum network applications using semiconductor-based spin-to-photon interfaces and coherently coupled nuclear spins.