Room temperature optically detected magnetic resonance in single spins hosted in GaN

Optically detected magnetic resonance (ODMR) is an efficient mechanism to readout the spin of solid-state color centers at room temperature, thus enabling spin-based quantum sensors of magnetic field, electric field, and temperature with high sensitivity and broad commercial applicability. The mechanism of room temperature ODMR is based on spin-dependent relaxation between the optically excited states to the ground states, and thus it is an intrinsic property of a defect center. In this presentation, we demonstrate that bright-and-narrow-linewidth single photon emitters previously reported in GaN can be categorized into two distinct groups based on their ODMR signatures. A less abundant group (group I) has a small negative ODMR contrast based on a S≥1 spin, whereas the more abundant group (group II) has large (up to ~30%) positive ODMR contrast based on a S≥3/2 spin. Furthermore, time-resolved photoluminescence shows that the spin levels reside in the metastable state for group-I defects but, in contrast, ground/excited states for group-II defects. Because GaN is a mature semiconductor with well-developed electronic technologies, this defect platform is promising for integrated quantum sensing applications.