Phase field predictions of the domain wall topology of BiFeO₃

Recently, BiFeO₃ has been shown to display interesting coupling between the multiferroic order parameters leading to the formation of chiral antiferromagnetic polar domain walls [1]. Utilizing the phase field method and a free energy parameterized by first principles calculations [2], we explore the zoology of the different domain walls that can arise in this material. Specifically, we focus on the predictions of the coupled polarization, oxygen octahedral tilt, and strain tensor components at these regions of interest. Our calculations reveal the presence of Bloch-like components which may influence the system’s noncollinear magnetism or the formation of topologically non-trivial states. We investigate the sensitivity of these features and corresponding domain wall thicknesses on the Lifshitz invariants (gradient terms) and also compare the results to predictions of domain wall profiles found from DFT calculations and observations from experiments.

[1] Chauleau, J. Y. et al., Nature Mater. 19, 386 (2020)

[2] Fedorova, N, Nikonov, D., Young, I. and Iniguez, J. in preparation. (2021)