First-principles local-stress calculations for oxygen vacancies in silicon oxide glass materials

We systematically investigated the correlation between defect formation energy and local stress states in amorphous ${\mathrm{SiO}}_{2}$ (a-${\mathrm{SiO}}_{2}$) using first-principles calculations within density functional theory. Although conventional approaches require the structural relaxation of oxygen vacancy at each site, we demonstrated that the formation tendency of oxygen vacancies can be quantitatively predicted from the local stress state in a nondefective system. To achieve this, we employed a real-space analysis based on Bader partitioning and introduced a unit-based averaging method for local structural units, enabling physically meaningful stress evaluations in ionically disordered systems. A strong statistical correlation was found between the formation energy and the unit-averaged stress in the Si--O--Si unit, suggesting that the local compressive environments significantly facilitated oxygen removal with large structural relaxation. These results establish a predictive framework for identifying defect-prone sites in disordered systems, including amorphous structures, without exhaustive defect structure generation, thereby offering an efficient route for defect analysis and material design.