Density-functional calculations are performed to study the effect of epitaxial strain on PbZrO${}_3$. We find a remarkably small energy difference between the epitaxially strained polar $R3c$ and nonpolar Pbam structures over the full range of experimentally accessible epitaxial strains $-3\%⩽\eta ⩽4\%$. While ferroelectricity is favored for all compressive strains, for tensile strains the small energy difference between the nonpolar ground state and the alternative polar phase yields a robust antiferroelectric ground state. The coexistence of ferroelectricity and antiferroelectricity observed in thin films is attributed to a combination of strain and depolarization field effects.

• Received 30 July 2013

DOI:https://doi.org/10.1103/PhysRevB.88.180102