Optically interfaced solid-state defects are promising candidates for quantum communication technologies. The ideal defect system would feature bright telecom emission, long-lived spin states, and a scalable material platform, simultaneously. Here, we employ one such system, vanadium (V4+) in silicon carbide (SiC), to establish a potential telecom spin-photon interface within a mature semiconductor host. This demonstration of efficient optical spin polarization and readout facilitates all optical measurements of temperature-dependent spin relaxation times (T1). With this technique, we lower the temperature from about 2K to 100 mK to observe a remarkable four-orders-of-magnitude increase in spin T1 from all measured sites, with site-specific values ranging from 57 ms to above 27 s. Furthermore, we identify the underlying relaxation mechanisms, which involve a two-phonon Orbach process, indicating the opportunity for strain-tuning to enable qubit operation at higher temperatures. These results position V4+ in SiC as a prime candidate for scalable quantum nodes in future quantum networks.
@article{arxiv.2405.16303,
title = {Extended spin relaxation times of optically addressed telecom defects in silicon carbide},
author = {Jonghoon Ahn and Christina Wicker and Nolan Bitner and Michael T. Solomon and Benedikt Tissot and Guido Burkard and Alan M. Dibos and Jiefei Zhang and F. Joseph Heremans and David D. Awschalom},
journal= {arXiv preprint arXiv:2405.16303},
year = {2024}
}