Open AccessFirst-principles study of ordered structures in Ba0.5Sr0.5TiO3
Author(s) -
Jiaqing He,
WenZhong Lu,
Xiaohong Wang
Publication year - 2011
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.60.097102
Subject(s) - octahedron , tetragonal crystal system , materials science , ferroelectricity , crystallography , condensed matter physics , antiferroelectricity , atom (system on chip) , center (category theory) , phase (matter) , dielectric , crystal structure , chemistry , physics , computer science , optoelectronics , organic chemistry , embedded system
The lattice structures and the electronic structures of different ordered structures in Ba0.5Sr0.5TiO3 are calculated by the first-principles method. The results of geometry structures and overlap populations reveal that the BST{100} ordered structure is tetragonal. The O atoms in Ti-O octahedron parallel to Ba plane and Sr plane are shifted ward Sr plane by 0.065 Å. And the Ti atom in Ti-O octahedron has a off-center displacement of 0.040 Å. The off-center displacements of O atoms and Ti atoms result in the distortion of Ti-O octahedron, and the occurrence of antiparallel spontaneous polarization. Therefore the BST{100} ordered structure is in antiferroelectric phase. The O atoms in BST{110} ordered structure also have a off-center displacement of 0.029 Å, while the Ti atom in Ti-O octahedron is still in-center. This tetragonal structure is in paraelectric phase. The BST{111} ordered structure is in cubic paraelectric phase. The calculated density of states shows that the hybridization between Ti 3d and O 2p plays a primary role in the generation of ferroelectricity. The results of the present work imply that the local order of A site can significantly influences the structural phase transition of disordered BST solid solution.