High-throughput discovery of complex spin defects in silicon for quantum technologies

Defect spin qubits in semiconductors have emerged as a promising platform for realizing spin–photon interfaces in quantum communication technologies. Among potential hosts, silicon is particularly appealing due to its mature nanofabrication infrastructure and compatibility with large-scale integration. The silicon T-center exemplifies these advantages and offers long spin coherence and telecom-band optical emission mediated by a defect-bound exciton—a mechanism distinct from the in-gap defect level transitions of color centers such as the nitrogen-vacancy center in diamond. To explore new quantum defect candidates in silicon, we build a first-principles computational database of over 20,000 impurity- and vacancy-related complexes and systematically survey the defect energetics and optical properties. Leveraging data-driven screening, we identify potential defect candidates, discuss the associated challenges and emerging design principles for engineering quantum defects in narrower-bandgap hosts to enable telecom-wavelength spin–photon interfaces.