Interatomic potential optimization to determine phase transitions in PbTiO₃ based on phonon dispersion

When exploring new ferroelectric materials computationally, it is necessary to consider the temperature dependence and physical properties of the structure. In the present study, we used a classical molecular dynamics simulation to investigate phase transitions during high-temperature annealing of KNbO3. The results revealed that a supercell larger than 8 × 8 × 8 is required to reproduce the phase transitions clearly. We also attempted to establish a method for obtaining the interatomic potential for any alloy composition. For PbTiO3, this was achieved using genetic algorithm fitting, and a phonon dispersion curve similar to that simulated by first-principles calculation was obtained.