First-principle study on the effects of electric field and anisotropic oxygen vacancy on dielectric properties of rutile titanium dioxide

¹ School of Electronics and Information Engineering, Soochow University, Suzhou 215021, P.R. China
² The 26th Institute of China Electronics Technology Group Corporation, Chongqing 400060, P.R. China
³ Institute of Intelligent Structure and System, School of Urban Rail Transportation, Soochow University, Suzhou 215006, P.R. China

^a e-mail: mail lingfeng@aliyun.com

Received: 25 April 2014
Revised: 31 July 2014
Accepted: 20 August 2014
Published online: 7 November 2014

Abstract

First principles studies about the influence of electric field and anisotropic oxygen vacancy on the dielectric properties of rutile titanium dioxide (TiO₂) are investigated. These results demonstrate that dielectric properties of perfect TiO₂ presents dependent on the low electric field that less than 5.2 MV/cm. As a comparison, the dielectric properties of defected TiO₂ in (1 1 0) plane and [1 1 0] direction show more sensitive to high electric field. Further more, considering the different positions of oxygen vacancy, the oxygen vacancy locates in (1 1 0) plane of defected TiO₂ appears more active to high electric field than it does in [1 1 0] direction. The effect of electric field and oxygen vacancy induce the distorted supercell structure and broken bond between the nearer oxygen atoms and titanium atoms. Moreover, the oxygen vacancy locates in (1 1 0) plane of defected TiO₂ can create more potential broken bond. These results account for the difference of dielectric properties in perfect TiO₂ and defected TiO₂.