Understanding the origin of defect-based single-photon emission in nitride materials

Wide-bandgap nitride materials host promising defect-based single-photon emitters, motivating efforts to clarify their microscopic origin and the role of vibronic effects. We investigate defect-driven single-photon emission in AlN, GaN, and hBN with the objective of identifying localized vibrational modes associated with defect states involving N₂ dimers and assessing their contribution to the vibronic fingerprints observed in photoluminescence (PL) and resonant inelastic X-ray scattering (RIXS) spectra. By combining first-principles molecular dynamics with many-body perturbation theory (GW-BSE), we explore a range of defect configurations and characterize their electronic and vibronic properties. Our results highlight specific defect-induced vibronic couplings involving donor–acceptor pairs that are common to AlN, GaN, and hBN, and may underpin robust solid-state single-photon emission in nitride-based platforms.