Developing a force field for the Ba1-xCaxZrO3 ferroelectric alloy: Prediction of a ferroelectric superlattice structure

J Zhang and Y Qi and AM Rappe, PHYSICAL REVIEW B, 105, 214204 (2022).

DOI: 10.1103/PhysRevB.105.214204

In this study, we develop a classical interatomic potential for the Ba1-xCaxZrO3 alloy based on the bond-valence theory. The bond-valence model enables rapid and large-scale molecular dynamics simulations of alloys with variable compositions. Molecular dynamics simulations based on this force field can reproduce the experimentally observed composition-dependent dielectric responses and lattice constants very well, indicating the validity and robustness of this force field. Based on molecular dynamics simulations, we demonstrate that Ba1-xCaxZrO3 can adopt a ferroelectric phase under a tensile strain, while the Ba1-xCaxZrO3 solid solution under zero strain is paraelectric. In addition, we find that strain can invoke a phase transition from antiferroelectric to ferroelectric in the BaZrO3/CaZrO3 superlattice. These results successfully explain previous experimental results and first-principles calculations. This interatomic potential provides a powerful tool for simulating the physical properties of perovskite alloys at nanoscale and thus has great significance in understanding the underlying physical mechanisms and designing functional materials.

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