Coherence of NV defects in isotopically enriched 6H-28SiC at ambient conditions

The unique spin-optical properties of NV defects in SiC, coupled with silicon carbide's advanced technology compared to diamond, make them a promising candidate for quantum technology applications. In this study, using photoinduced pulse ESR at 94 GHz (3.4 T), we reveal the room temperature spin coherence of NV defects in 6H-28SiC, purified to reduce 29Si concentration to ≈1%, four times below its natural level. We demonstrate room temperature (300 K) Hahn-echo coherence time T2 = 23.6 μs, spin–lattice relaxation time T1 = 0.1 ms, and coherent control over optically polarized NV spin states through Rabi nutation experiments. We reveal long inhomogeneous dephasing time T2* = 1.5 μs, which is about five times greater than that measured for NV defects in SiC with natural isotopic content. Our observations highlight again the potential of NV defects in 6H-28SiC, which exhibit near-infrared optical excitation and emission properties compatible with O-band fiber optics, as promising candidates for applications in quantum sensing, communication, and computation.