Electronic structures and ferroelectric instabilities of cubicAV O3 (A = Sr, Ba, and Pb) perovskites by first-principles calculations

Abstract

The electronic properties and ferroelectric transition behaviors of threeAV O3 (A = Sr, Ba, and Pb) compounds are investigated by first-principles density functionaltheory (FP-DFT) in combination with soft-mode theory. The band structuresand projection density of states (PDOS) confirm that the bonding properties ofSrV O3 andBaV O3 are rather similar to each other, but different to that ofPbV O3.The bonding differences determine the ferroelectric transition behaviors of these compounds. ForSrV O3 andBaV O3, no ferroelectric instability is observed and they possess cubic structures. The covalentinteractions of Pb–O pairs are very important for the ferroelectric instability ofPbV O3. In comparisonto PbTiO3, we found that the V–O interactions further enhance the ferroelectric instability ofPbV O3, andtherefore PbV O3 shows a much larger tetragonal distortion thanPbTiO3.