Scalable quantum networks require stablequantum platforms with quantum processing capabilities and a reliablespin-optical interface. The search for ideal systems is still ongoing, astoday’s available platforms suffer from too large electron phonon interactionand/or spectral diffusion.

Recent progress in the field of color defects as quantum systems in 4H-SiC showed that the negatively charged silicon vacancy center in siliconcarbide is immune to both drawbacks. Thanks to its 4A2 symmetry inground and excited states, optical resonances are stable with near Fouriertransform limited linewidths. In combination with millisecond long spincoherence times originating from the high purity crystal, a high fidelityoptically-assisted spin initialization and coherent control was presented.Crucially, the result showed coherent coupling to single nuclear spins with ~1kHz resolution, which is sufficient to implement quantum memories and quantumerror correction.

The summary of the findings makes the siliconvacancy in silicon carbide a prime candidate for realizing memory-assistedquantum network applications using semiconductor-based spin-to-photoninterfaces and coherently coupled nuclear spins.

References: Nagy  et al., Nature Communications 10, 1954 (2019)