LAUSR

Atomlike defect levels in silicon carbide (SiC) polytypes have been proposed and proven to be an excellent platform for various quantum technology applications. Single-photon emitters, coherent control at room temperature, and temperature and magnetic field sensing at the nanoscale have already been demonstrated for the case of vacancy and divacancy defects in SiC and more recently proposed for negatively charged NV centers. NV centers, which allow a better control of their generation, offer in addition a further shift of the spectral range in the near infrared, i.e., in the $O$- and $S$-band telecom range. We demonstrate here that the association of high resolution optical spectroscopy and electron paramagnetic resonance spectroscopy combined with first-principles calculations allow the identification of the microscopic structure of the six distinct NV centers in $6H\ensuremath{-}\mathrm{SiC}$ and the assignment of their associated zero-phonon photoluminescence lines. Time resolved photo-EPR measurements at $T=4\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ show that NV centers in $6H\ensuremath{-}\mathrm{SiC}$ present spin lattice relaxation times of several seconds. These excellent qubit properties should enable their application and implementation in quantum information devices.