Antiferroelectricity in thin-filmZrO2from first principles

Density-functional calculations are performed to investigate the experimentally reported field-induced phase transition in thin-film ${\mathrm{ZrO}}_2$ [J. Müller et al., Nano Lett. 12, 4318 (2012)]. We find a small energy difference of $\sim 1$ meV/f.u. between the nonpolar tetragonal and polar orthorhombic structures, characteristic of antiferroelectricity. The requisite first-order transition between the two phases, which atypically for antiferroelectrics have a group-subgroup relation, results from coupling to other zone-boundary modes, as we show with a Landau-Devonshire model. Tetragonal ${\mathrm{ZrO}}_2$ is thus established as a lead-free antiferroelectric with excellent dielectric properties and compatibility with silicon. In addition, we demonstrate that a ferroelectric phase of ${\mathrm{ZrO}}_2$ can be stabilized through epitaxial strain, and suggest an alternative stabilization mechanism through continuous substitution of Zr by Hf.