Finite-temperature properties of the antiferroelectric perovskite PbZrO3 from a deep-learning interatomic potential

HZ Zhang and HC Thong and L Bastogne and CR Gui and X He and P Ghosez, PHYSICAL REVIEW B, 110, 054109 (2024).

DOI: 10.1103/PhysRevB.110.054109

The prototypical antiferroelectric perovskite PbZrO3 (PZO) has garnered considerable attention in recent years due to its significance in technological applications and fundamental research. Many unresolved issues in PZO are associated with large length- and time-scales, as well as finite temperatures, presenting significant challenges for first- principles density functional theory studies. Here, we introduce a deep- learnining interatomic potential of PZO, enabling investigation of finite-temperature properties through large-scale atomistic simulations. Trained using an elaborately designed dataset, the model successfully reproduces a large number of phases, in particular, the recently discovered 80-atom antiferroelectric Pnam phase and ferrielectric Ima2 phase, providing precise predictions for their structural and dynamical properties. Using this model, we investigated phase transitions of multiple phases, including Pbam/Pnam, Ima2, and R3c, which show high similarity to the experimental observation. Our simulation results also highlight the crucial role of free energy in determining the lowtemperature phase of PZO, reconciling the apparent contradiction: Pbam is the most commonly observed phase in experiments, while theoretical calculations predict other phases exhibiting even lower energy. Furthermore, in the temperature range where the Pbam phase is thermodynamically stable, typical double polarization hysteresis loops for antiferroelectrics were obtained, along with a detailed elucidation of the structural evolution during the electric-field induced transitions between the nonpolar Pbam and polar R3c phases.

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