First-principles Landau-like potential for BiFeO3 and related materials

Auteurs

Fedorova N.S., Nikonov D.E., Li H., Young I.A., Íñiguez J.

Référence

Physical Review B, vol. 106, n° 16, art. no. 165122, 2022

Description

In this paper, we introduce the simplest, lowest-order Landau-like potential for BiFeO3 and La-doped BiFeO3 as an expansion around the paraelectric cubic phase in powers of polarization, FeO6 octahedral rotations, and strains. We present an analytical approach for computing the model parameters from density-functional theory. We illustrate our approach by computing the potentials for BiFeO3 and La0.25Bi0.75FeO3 and show that, overall, we are able to capture the first-principles results accurately, including properties that were not considered for the calculation of the model parameters. The computed models allow us to identify and explain the main interactions controlling the relative stability of the competing low-energy phases of these compounds.

Lien

doi:10.1103/PhysRevB.106.165122