INVESTIGADORES
STACHIOTTI Marcelo Gabriel
artículos
Título:
Temperature-driven phase transitions in SrBi2Ta2O9 from first-principles calculations
Autor/es:
R. MACHADO; M. SEPLIARSKY; M.G.STACHIOTTI
Revista:
APPLIED PHYSICS LETTERS
Editorial:
AMER INST PHYSICS
Referencias:
Año: 2008 vol. 93 p. 242901 - 242901
ISSN:
0003-6951
Resumen:
The phase transition sequence of SrBi2Ta2O9 is investigated using a shell model with parameters fitted to first-principles calculations. We show that the complex interplay between polar and nonpolar instabilities leads to the presence of two phase transitions, corroborating the existence of an intermediate orthorhombic paraelectric phase. This phase is characterized by the rotation of the TaO6 octahedra around the a axis. We show that this phase can also be detected from the dielectric response of the material. The present approach constitutes a powerful tool for a theoretical prediction of intermediate phases, not yet observed experimentally, in other Aurivillius compounds.
