Abstract
Density-functional calculations are performed to investigate the experimentally reported field-induced phase transition in thin-film [J. Müller et al., Nano Lett. 12, 4318 (2012)]. We find a small energy difference of 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 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 can be stabilized through epitaxial strain, and suggest an alternative stabilization mechanism through continuous substitution of Zr by Hf.
- Received 25 March 2014
- Revised 16 September 2014
DOI:https://doi.org/10.1103/PhysRevB.90.140103
©2014 American Physical Society