超高压下钙钛矿材料铁电峰值行为研究.

Pressure has significant influences on the crystal structures and functional properties of perovskite ferroelectric materials, but relatively minor impact on the phase transition temperature, and can serve as an effective means to enhance the dielectric and ferroelectric properties of these materials. Molecular dynamics simulations were conducted based on the first principles to explore the evolution of ferroelectricity in barium titanate (BTO) single crystals subjected to hydrostatic pressures ranging from the atmospheric pressure to 150 GPa. The findings demonstrate that, a non-monotonic trend of the ferroelectricity of BTO occurs with the increase of the pressure. The ferroelectric first weakens, then intensifies, and finally disappears, with a peak at 42 GPa. This behavior can be attributed to the pressure-induced reduction in atomic spacings. This reduction disrupts the delicate balance between long-range Coulomb forces and short-range electron repulsions. The findings elucidate the ferroelectric behavior of BTO single crystals under ultra-high hydrostatic pressure, providing a theoretical foundation for their future applications to devices and offering valuable theoretical guidance for experimental investigations of BTO ferroelectricity under ultra-high pressures. [ABSTRACT FROM AUTHOR]