Electrical phase diagram of bulk BiFeO₃

Auteurs

M. Stengel and J. Iñiguez

Référence

Physical Review B, vol. 92, no. 23, art no. 235148, 2015

Description

We study the electrical behavior of multiferroic BiFeO₃ by means of first-principles calculations. We do so by constraining a specific component of the electric displacement field along a variety of structural paths, and by monitoring the evolution of the relevant physical properties of the crystal along the way. We find a complex interplay of ferroelectric, antiferroelectric, and antiferrodistortive degrees of freedom that leads to an unusually rich electrical phase diagram, which strongly departs from the paradigmatic double-well model of simpler ferroelectric materials. In particular, we show that many of the structural phases that were recently reported in the literature, e.g., those characterized by a giant aspect ratio, can be in principle accessed via application of an external electric field starting from the R3c ground state. Our results also reveal ways in which nonpolar distortions (e.g., the antiferrodistortive ones associated with rotations of the oxygen octahedra in the perovskite lattice) can be controlled by means of applied electric fields, as well as the basic features characterizing the switching between the ferroelectric and antiferroelectric phases of BiFeO₃. We discuss the multimode couplings behind this wealth of effects, while highlighting the implications of our work as regards both theoretical and experimental literature on BiFeO₃.

Lien

doi:10.1103/PhysRevB.92.235148