Electric coupling and long dephasing times of single defect spins in commercial 4H-SiC

Divacancies (VV) in silicon carbide (SiC) are a promising platform for quantum communication owing to their long-lived spin coherence [1] and high-fidelity spin-to-photon interface [2] in a wafer-scale host material. Here, we investigate the properties of single basal kh VV in commercially available 4H-SiC. We report an electronic ground-state spin dephasing time (T₂*) exceeding 60 µs for a single kh VV at 4 K, which is among the longest reported in a naturally abundant host. Furthermore, the C_1h symmetry of kh VV quenches dynamic Jahn-Teller distortions, leading to long optical coherence and excited-state energy level coupling with ac electric fields. We observe optical Rabi oscillations with coherence times approaching the lifetime limit, permitting high-visibility quantum interference of emitted photons. We demonstrate coupling between excited-state energy levels and ac electric fields through the observation of a Floquet-dressed optical spectrum. These robust spin and optical properties make the kh VV a versatile candidate for quantum information processing and hybrid system applications.

[1] Seo, H. et al. Nat. Commun. 7, 12935 (2016).
[2] Christle, D. et al. Phys. Rev. X. 7, 021046 (2017).