Spontaneous Polarization and Local Structures in Ca-substituted BaTiO₃

Abstract

We have investigated the local structure and spontaneous polarization (P_s) of Ba_1-xCa_xTiO₃ (BCT) by density functional theory (DFT) calculations. The DFT calculations based on a supercell approach show that Ca atoms are markedly displaced cooperatively with the adjacent Ti atoms along the P_s direction. It is suggested that the CaTiO₃-like octahedral rotation is constructed in the BCT supercell around the Ca atoms, which is the origin of the smaller P_s of BCT.