Isolate quantum defects in wide-bandgap materials

Isolated quantum defects in wide-bandgap materials play a crucial role in tuning electronic, optical, and quantum properties, enabling advancements in quantum information devices. Using first-principles calculations, we investigate such defects in wide-band gap materials. The NV⁻ center in diamond, a promising candidate for quantum sensing and qubit applications, exhibits pressure-dependent variations in ionization potential, zero-phonon line, and zero-field splitting. Similarly, Er-doped CaWO₄ shows potential for quantum repeaters and single-photon emitter applications; however, our findings reveal that oxygen- and calcium-related defects predominate, forming charged complexes with Er dopants. Understanding these defects provides critical insights for advancing electronic, photonic, and quantum technologies.