Electronic and structural properties of [MathML equation]: A proposal about the role of Ti 3s and 3p states for ferroelectricity

• Published in: Solid state communications Vol. 150; no. 3-4; pp. 205 - 208
• Main Authors: Miura, Kaoru, Furuta, Tatsuo, Funakubo, Hiroshi
• Format: Journal Article
• Language: English
• Published: 01.01.2010
• ISSN: 0038-1098
• DOI: 10.1016/j.ssc.2009.10.037

We have investigated the role of the Coulomb repulsions between Ti 3s and 3p states and O 2s and 2p states in ferroelectric BaTiO(3), using a first-principles calculation with optimized structures. It has been found that the Coulomb repulsions between Ti 3s and [MathML equation] states and [MathML equation] 2s and [MathML equation] states are closely related to the appearance of Ti ion displacement in tetragonal BaTiO(3). The mechanism of the Ti-O Coulomb repulsions also seems to be consistent with the appearance of Ti ion displacement in rhombohedral BaTiO(3). Our investigation suggests that the Coulomb repulsions between Ti 3s and [MathML equation] states and [MathML equation] 2s and [MathML equation] states have an important role in the appearance of the ferroelectric state in tetragonal BaTiO(3).