Influence of in-plane biaxial stress on the structural properties, ferroelectric response, and piezoelectricity of tetragonal PbTiO3

Tetragonal PbTiO3 under in-plane biaxial stress is investigated from first principles. We show that before the biaxial tensile stress applied in the plane perpendicular to the c axis reaches its ideal tensile strength of 28.95 GPa, PbTiO3 tend to show the paraelectric tetragonal symmetry. We also find that the biaxial tensile stress can enhance the piezoelectric stress coefficients, whereas the biaxial compressive stress can enhance the piezoelectric strain coefficients. The underlying mechanisms for the predicted piezoelectric responses are also discussed.