Theoretical investigation on BaTiO3 with periodic density functional theory BLYP method

Chen, ZX Liu, CG Chen, Y Jiang, YS

Zx. Chen et al., Theoretical investigation on BaTiO3 with periodic density functional theory BLYP method, CHEM PHYS, 270(2), 2001, pp. 253-261

47

INGLESE

Article

Physical Chemistry/Chemical Physics

CHEMICAL PHYSICS

0301-0104 → ACNP

270

2

2001

253 - 261

ISI

0301-0104(20010801)270:2<253:TIOBWP>2.0.ZU;2-#

The electronic structures and bonding modes of BaTiO3 in the cubic and the distorted tetragonal structures have been investigated with periodic DFT-BL YP method. The results show that Ti displacement makes the charge transfer from O atoms to Ba and Ti atoms. Ba atoms might play a more important role in distributing the transferred charges than one has imagined. Our results also indicate that Ti displacement enhances the Ti-O and Ba-O(2) bonds. Onl y Ba-O(1) is slightly weakened. The pi bonding interaction of 3d(xz)(Ti)-2p (x)[O(1)] and 3d(yz)(Ti)-2p(y)[O(1)] favors the tetragonal phase whereas th e a bond 4p(z)(Ti)-2p(z)[O(1)] favors the paraelectric cubic phase. Our res ults are consistent with the vibronic theory that the ferroelectric instabi lity of BaTiO3 is due to the formation of new covalency by distortion. (C) 2001 Elsevier Science B.V. All rights reserved.