Comparison of interatomic potential models on the molecular dynamics simulation of fast-ion conductors: A case study of a Li garnet oxide Li7La3Zr2O12

In this work, we performed molecular dynamic simulations of a representative fast-ion conductor (Li7La3Zr2O12) using three different interatomic potential models: non-polarizable core (Core), polarizable core-shell (CS), and induced dipole (ID). To compare these three models, we calculated the phase transition behavior, self-diffusivity, ionic conductivity, dielectric constant, and elastic moduli of Li7La3Zr2O12 and checked results against experimental and other simulation work. We found that overall all three potential models predict results that agree reasonably well with experiments and first-principles calculations. However, we think that the ID model that combines both force-matching, atomic polarization, and first-principles charge has the technical advantage over the other two, while exhibiting slightly higher computational cost. We also discussed ways to further improve these interatomic potential models.