Generation of Spin Defects in Hexagonal Boron Nitride

Two-dimensional hexagonal boron nitride offers intriguing opportunities for advanced studies of light-matter interaction at the nanoscale, specifically for realizations in quantum nanophotonics. Here, we demonstrate the generation of optically addressable spin defects based on the negatively charged boron vacancy (V-B(-)) center. We show that these centers can be created in exfoliated hexagonal boron nitride using a variety of focused ion beams (nitrogen, xenon, and argon). Using a combination of laser and resonant microwave excitation, we carry out optically detected magnetic resonance spectroscopy measurements, which reveal a zero-field ground state splitting for the defect of similar to 3.46 GHz. We also perform photoluminescence excitation spectroscopy and temperature-dependent photoluminescence measurements to elucidate the photo-physical properties of the V-B(-) centers. Our results are important for advanced quantum and nanophotonics realizations involving manipulation and readout of spin defects in hexagonal boron nitride.