Copper–vacancy center in gallium oxide: A telecom quantum defect

Quantum defects in wide-bandgap semiconductors have emerged as promising platforms for quantum information technologies, offering optically addressable spin states and single-photon emission. Defects emitting at telecom wavelengths are particularly attractive for quantum networking applications due to compatibility with existing fiber-optic infrastructure. Here, we employ first-principles calculations to identify a previously observed telecom emitter in β-Ga2O3 as a hydrogenated copper–vacancy center. We propose that previously observed emission at 1316 nm arises from one of four hydrogenated copper–vacancy configurations. Through comparisons with earlier experimental characterization, including photoluminescence, photoluminescence excitation, and zero-field splitting, we conclude that the singly hydrogenated ib configuration is the most likely candidate. These centers exhibit spin-1 ground states with large zero-field splitting and strong zero-phonon emission lines: characteristics essential for quantum applications. Our results establish hydrogenated copper–vacancy centers in gallium oxide as promising telecom quantum defects and provide a roadmap for engineering quantum emitters in wide-bandgap oxides.