We investigate the electrostrictive response across a ferroelectric phase transition from first-principles calculations and show that $M$, the field-induced electrostrictive tensor, controlling the amplitude of the electric-field induced strain, can be made arbitrarily large through strain engineering. We take as a case study the epitaxial strain-induced transition from para- to ferroelectricity of ${\mathrm{KTaO}}_3$. We show that the magnitude of the field-induced electrostriction diverges with the permittivity at the transition, hence exhibiting giant responses through a calculation of both the $M$ and $Q$ electrostrictive tensors. We explain the origin of this giant electrostrictive response in ${\mathrm{KTaO}}_3$ using a microscopic decomposition of the electrostriction coefficients, and use this understanding to propose design rules for the development of future giant electrostrictors for electromechanical applications. Finally, we introduce a further means to calculate electrostriction, specific to ferroelectrics, and not yet utilized in the literature.

• Received 24 November 2021
• Accepted 14 July 2022

DOI:https://doi.org/10.1103/PhysRevB.106.L060102