Influence of uniaxial tensile stress on the mechanical and piezoelectric properties of short-period ferroelectric superlattice

TL;DR

This study investigates how uniaxial tensile stress affects the mechanical strength and piezoelectric properties of BaTiO3/PbTiO3 ferroelectric superlattices, revealing significant enhancements in piezoelectric response.

Contribution

It provides first-principles insights into stress-induced modifications of ferroelectric superlattices, highlighting a method to substantially boost piezoelectricity.

Findings

Ideal tensile strength is 6.85 GPa.

Uniaxial tensile stress softens the superlattice along nonpolar axes.

Piezoelectric coefficient d33 increases by about 8 times, reaching 678.42 pC/N.

Abstract

Tetragonal ferroelectric/ferroelectric BaTiO3/PbTiO3 superlattice under uniaxial tensile stress along the c axis is investigated from first principles. We show that the calculated ideal tensile strength is 6.85 GPa and that the superlattice under the loading of uniaxial tensile stress becomes soft along the nonpolar axes. We also find that the appropriately applied uniaxial tensile stress can significantly enhance the piezoelectricity for the superlattice, with piezoelectric coefficient d33 increasing from the ground state value by a factor of about 8, reaching 678.42 pC/N. The underlying mechanism for the enhancement of piezoelectricity is discussed.