(Ba,K,La) ZrO3 as a possible lead-free ferroelectric: Density functional calculations

Abstract

First-principles supercell calculations are used to investigate the lattice distortions in BaZrO3 heavily codoped with K and La. We find that nonferroelectric BaZrO3 can be made ferroelectric in this way. The ferroelectricity is the result of La off-centerings and can be understood using ionic size considerations. In particular, size disorder on the perovskite A site suppresses the tendency toward octahedral tilts with substitution of the small La ion. This results in A -site driven ferroelectricity. © 2008 The American Physical Society.