Phase transitions and antiferroelectricity inBiFeO3from atomic-level simulations

Abstract

The structural and polar properties of BiFeO3 at finite temperature are investigated using an atomistic shell model fitted to first-principles calculations. Molecular

Dielectric and piezoelectric properties of BiFeO3 from molecular dynamics simulations

“…The hightemperature Pbnm phase is characterized by two sublattices with opposite polarizations, generated by Bi off-center displacements. This feature supports the antiferroelectric nature of the Pbnm phase [20]. The oxygen octahedron tilting becomes in-phase along z while it remains out-of-phase along the other two directions.…”

“…See Ref. [20] for details about the parametrization of the model for BFO. In this work we apply the interatomic potentials developed for BFO to determine the dielectric and piezoelectric properties of this material at finite temperature.…”

“…The polar nature of the high-temperature phase is also not settled. While this phase has been seen as paraelectric in experiments, signals related to an antiferroelectric (AFE) order have been suggested [17][18][19][20].…”

“…Given this controversial experimental background, the determination of the intrinsic properties of BFO using a reliable theoretical approach is highly desirable. In this paper we report the dielectric and piezoelectric properties of BFO using a first-principles based atomistic model, which has the advantage of accurately predicting the temperature-driven phase transition sequence of the material [20].…”

BiInO3 phases under asymmetric in-plane strain

“…Since a DFTbased run would be computationally too demanding, the USPEX predictions are instead performed with the force field lattice program GULP [11,12]. The corresponding interatomic potentials are derived from a core-shell model based on Rydberg potentials that has been successfully applied to model BiFeO 3 properties before [13]. The potential parameters are then fitted to the 6 structures studied by DFT and their energies (see the supplemental S1 for the full parameter set).…”