The Structural and Electronic Properties of BaO under Epitaxial Strains: First-Principles Calculations

The structural and electronic properties of alkaline-earth oxide BaO under epitaxial strains are investigated using a first principles density functional theory. The electronic structure is particularly sensitive to the compressive or tensile strain, e.g., the splitting of energy band, the increase of the total density of state, and the shift of the partial density of states. Especially, the trends in the variation of the optical band gap are predicted by two different exchange-correlation potential schemes. Our results indicate that the optical band gaps undergo a decrease for both compressive and tensile strains.