%0 Journal Article
%T Phase Transitions and Antiferroelectrivity in BiFeO3 from Atomic Level Simulations
%A M. Graf
%A M. Sepliarsky
%A S. Tinte
%A M. G. Stachiotti
%J Physics
%D 2014
%I arXiv
%R 10.1103/PhysRevB.90.184108
%X The structural and polar properties of BiFeO3 at finite temperature are investigated using an atomistic shell model fitted to first-principles calculations. Molecular Dynamics simulations show a direct transition from the low-temperature R3c ferroelectric phase to the Pbnm orthorhombic phase without evidence of any intermediate bridging phase between them. The high-temperature phase is characterized by the presence of two sublattices with opposite polarizations, and it displays the characteristic double-hysteresis loop under the action of an external electric field. The microscopic analysis reveals that the change in the polar direction and the large lattice strains observed during the antiferroelectric-ferroelectric phase transition originate from the interplay between polarization, oxygen octahedron rotations and strain. As a result, the induced ferroelectric phase recovers the symmetry of the low temperature R3c phase.
%U http://arxiv.org/abs/1411.1777v1