High-Precision Angle-Resolved Magnetometry with Uniaxial Quantum Centers in Silicon Carbide

We show that uniaxial color centers in silicon carbide with hexagonal lattice structure can be used to measure not only the strength but also the polar angle of the external magnetic field with respect to the defect axis with high precision. The method is based on the optical detection of multiple spin resonances in the silicon vacancy defect with quadruplet ground state and suggests significant improvement of the angle sensitivity compared to spin-1 color centers. We demonstrate a good agreement between the experimental and calculated spin resonance spectra, providing angle resolution better than 1 degrees per Hz(1/2) in submillitesla magnetic fields. Our approach is suitable for ensemble as well as single spin-3/2 color centers, allowing for angle-resolved magnetometry on the nanoscale at ambient conditions.