We report an ab initio study of the elastic properties and energetics of the orthorhombic (AFO) and rhombohedral (RF) phases of ${\text{PbZrO}}_3$. We report the polarization for the RF phase and the elastic constants, the sound velocity, and the total energy for both phases. Our results show that the two phases are energetically close, by 2.3 mRy per formula unit, and the AFO phase is the most stable one consistent with the experimental phase diagram. The elastic constant and sound velocity calculations show that depending on the orientation, either phase can be the effectively stiffer one and that these differences are large. This suggests that control of the balance between these phases via strain is possible, for example, in epitaxy and in particular that the ferroelectric state can be stabilized even without lattice dilation.

• Received 8 October 2007

DOI:https://doi.org/10.1103/PhysRevB.77.104113