Octahedral distortion and electronic properties of the antiperovskite oxide Ba3SiO: First principles study

In this study, based on first principles calculations, we investigated the vibrational and electronic structure of the antiperovskite oxide Ba3SiO. The low temperature Pbnm structure was characterized in terms of the group-to-subgroup transition based on the vibrational modes obtained for the cubic Pm (3) over barm high-symmetry structure. We also observed a metal-to-insulator transition when passing from the cubic phase to the orthorhombic phase, which demonstrates the strong correlation between the octahedral rotations and tilting with respect to the electronic structure in Ba3SiO. Finally, we explored the xy biaxial strain as a control parameter for the structural and electronic degrees of freedom.