First principles prediction of a morphotropic phase boundary in the Bi(Zn1/2Ti1/2)O3-(Bi1/2Sr1/2)(Zn1/2Nb1/2)O3 alloy...

The magnitude and direction of polarization within alloys of the tetragonally distorted
Bi(Zn1/2Ti1/2)O3 (BZT) and the rhombohedrally oriented Bi1/2Sr1/2Zn1/2Nb1/2O3 (BSZN) are
explored using density functional theory. For compositions with 50% of BZT, we find that the
polarization points mainly along the [001] direction. Conversely, for low concentrations of BZT the
polarization is rhombohedrally oriented. Based on these results we propose a phase diagram with
a possible monoclinc phase between 25% and 50 % BZT where this material may have a useful
piezoelectric response.