IFIS - LITORAL   24734
INSTITUTO DE FISICA DEL LITORAL
Unidad Ejecutora - UE
artículos
Título:
Phase transitions and antiferroelectricity in BiFeO3 from atomic-level simulations
Autor/es:
M. GRAF; M. SEPLIARSKY; S. TINTE; M. G. STACHIOTTI
Revista:
PHYSICAL REVIEW B
Editorial:
AMER PHYSICAL SOC
Referencias:
Lugar: New York; Año: 2014 vol. 90 p. 184108 - 184115
ISSN:
1098-0121
Resumen:
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.