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

Abstract

First principles studies about the influence of electric field and anisotropic oxygen vacancy on the dielectric properties of rutile titanium dioxide (TiO 2 ) are investigated. These results demonstrate that dielectric properties of perfect TiO 2 presents dependent on the low electric field that less than 5.2 MV/cm. As a comparison, the dielectric properties of defected TiO 2 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 TiO 2 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 TiO 2 can create more potential broken bond. These results account for the difference of dielectric properties in perfect TiO 2 and defected TiO 2 .