Spin and optical properties of two-dimensional single color centers in hexagonal boron nitride

Quantum networks and sensing require solid-state spin-photon interfaces that combine single-photon generation and long-lived spin coherence with scalable device integration, ideally in ambient conditions. Although rarely combined in a single platform, access to quantum coherent, single-defect spins and Fourier-transform limited optical emission have been demonstrated at room temperature for different color centers in hexagonal boron nitride. We present quantum coherent control of a carbon-related defect species by optically detected magnetic resonance in ambient conditions. We demonstrate Rabi spin coherence times exceeding 1.2 µs and T1 spin relaxation times ranging from 35 to 200 µs, both at 0 mT magnetic field [1]. We identify a spin-triplet electronic ground state manifold, coupled predominantly to only a few proximal nuclei. Temperature-dependent spectroscopy further suggests mechanisms responsible for optical broadening, helping determine the limits for single-defect optical coherence. These results are an important step towards understanding defect spin and photo-dynamics, providing structural information to help unravel their potential as ambient temperature spin qubits or nanoscale-proximity quantum sensors.

1. H.L.Stern, C.M.Gilardoni, et al., arXiv.2306.13025 (2023).