Effects of lattice strain and ion displacement on the bonding mechanism of the ferroelectric perovskitematerial BaTiO3: first-principles study

Abstract

The effects of lattice strain and ion displacement on the bonding mechanism of the perovskite materialBaTiO3 have been studied by using the density-functional theory within the full-potential linearaugmented plane wave (FP-LAPW) method. The valence and the bonding charge density,the density of states (DOS), the local DOS and the partial DOS were calculated toinvestigate the bonding mechanisms. The charge transfer, along with the bonding process,was analysed by using the atoms in molecules theory (AIM). Based on the analysis of thebonding and the topological characteristics, the evolution of the bonding strength according todifferent lattice strains and ion displacements along with the phase transition ofBaTiO3 is shown quantitatively. Moreover, the evolution of the spontaneous polarization ofBaTiO3 corresponding to the ion displacements is also discussed by a modern theory of polarizationin the present paper.