Phase transition and antiferroelectricity in BiFeO3 from first-principles-based atomistic simulations,

GRAF, MONICA; SEPLIARSKY. MARCELO; TINTE, SILVIA; STACHIOTTI, MARCELO

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2014 vol. 90 p. 1841081 - 1841088

1098-0121

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 sublatticeswith 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 betweenpolarization, oxygen octahedron rotations, and strain. As a result, the induced ferroelectric phase recovers the symmetry of the low-temperature R3c phase.