First-principles study of oxygen vacancy formation in strained oxides

Based on first-principles density functional theory calculations and chemical bond analyses, we attempted to study the formation of oxygen vacancies (V-O) in strained Ti-based oxides. Structural features (e.g., cell volume and mean Ti-O bond length) exhibit a clear and linear correlation with strain. Further, electronic features (e.g., bandgap and Ti-O covalent bond strength) exhibit similar trends for hydrostatic, biaxial, and uniaxial strains, except for shear strains. We investigated the impact of strain on the formation of V-O and found that the formation energy in strained oxides was almost linearly linked to changes in the cell volume, bandgap, and Ti-O bond strength of the host oxide, where V-O were formed. However, these correlations are not valid in compressively strained systems, which include Ti-O bonds-the bond length being shorter than the sum of Ti and O ionic radii, and shear-strained systems.

Automated summary

In this study, the formation of oxygen vacancies in strained Ti-based oxides was investigated using first-principles density functional theory calculations and chemical bond analyses. The results showed clear correlations between structural features and strain, as well as similar trends for electronic features under different strains except for shear strains. The impact of strain on the formation of oxygen vacancies was also examined, revealing that the formation energy in strained oxides was linearly linked to changes in cell volume, bandgap, and Ti-O bond strength, except in compressively strained and shear-strained systems.