The Lattice Stabilities and Electronic Structure of Ba_xSr_{1 − x}TiO₃ Solid Solutions by First-Principles Calculations

Abstract

The structural, electronic, and optical properties of Ba _x Sr _{1 − x} TiO ₃ (BST, x = 0.125, 0.250, 0.500, 0.750 and 0.875) solid solutions were investigated by first-principles calculations within generalized gradient approximation based on density-functional theory. Stable lattice structures of cubic paraelectric phase are obtained in finding ground states. The energy bands structures, density of states and complex dielectric function are calculated from the stable structures. It is found that the lattice constants showed a linearly increase with x, which is consistent with Vegard's law. The analyses of the density of states and electron density difference conclude that the hybridization between Ba d and O p is stronger than that between Sr d and O p. From further analysis of the complex dielectric function, we get the static dielectric constant. The calculated results show good agreement with the available experimental and theoretical data.

Keywords:

• Perovskites
• Structural properties
• Electronic structure
• Optical properties