Magnetometry Based on Silicon-Vacancy Centers in Isotopically Purified 4H - SiC

Abstract

Point defects in solid-state materials are promising systems in the fields of quantum information, communications, and sensing. Particular to sensing, defects with coherent spin states are used for high-sensitivity room-temperature sensing under ambient conditions. Applications involving magnetic sensing with point defects are mostly dominated by the nitrogen-vacancy center in diamond, which possesses an attractive combination of spin coherence at room temperature as well as spin initialization and read-out. However, spin defects in other materials are explored as alternatives, especially in industrially mature materials, such as silicon carbide. Here, we report on the improved sensitivity of a magnetic sensor system utilizing an ensemble of silicon vacancies in silicon carbide due to isotopic purification of the host crystal. A maximum sensitivity of 4.0 nT/\ensuremath{\surd}Hz is reported, representing an order of magnitude improvement from the best previously reported sensitivity. Additional sensing modalities, such as angle-resolved magnetic imaging and highly broadband ac field sensing, are also demonstrated.