Ultrafast photoinduced strain in super-tetragonal PbTiO3 ferroelectric films

The ultrafast photoinduced strain (UPS) resulting from the coupling of piezoelectric and photovoltaic effects in ferroelectric has been focused last decade, endowing them with extensive applications including optical memories, sensors actuators engineering. mechanism screening depolarization field by carriers is generally accepted for UPS ferroelectrics, while thermal component usually diluted as offset not systematically confronted, leading to unnecessary confusion. Herein, both positive negative expansion composite epitaxial films are investigated use high-repetition-rate X-ray diffraction, along effects. positive/negative piezoelectric/photovoltaic evidenced can be regulated. opposite lattice responses due different samples axial ratios observed. maximum up 0.24%, comparable that conventional ferroelectric. interaction between induced could promote diversified light, heat electricity.