title: Anisotropic relaxation of a CuO/TiO2 surface under an electric field and its impact on visible light absorption: ab initio calculations.
abstract: Ab initio calculations on the anisotropic relaxation of a CuO/TiO2 surface under electric fields and the visible light absorption of these relaxed surfaces are reported. We compare the relaxation of the CuO/TiO2 surface under the electric fields in the direction of [001] or [010]. Fewer Cu-O bonds with highly coordinated Cu-ions are found in the CuO/TiO2 relaxed surface under the electric field in the [010] direction. The Cu-O bonds in the interface of the CuO/TiO2 surface led to an improved visible light absorption in the polarization direction of [001]. The CuO/TiO2 relaxed surface under the electric field in the [010] direction exhibits a more effective absorption of visible light. However, the electric field in the [001] direction induces more relaxation on the CuO/TiO2 surface, breaking the Cu-O bonds. This leads to the partial reduction of CuO to Cu2O on the CuO/TiO2 relaxed surface under the electric field in the [001] direction and inefficient absorption of visible light is observed for this surface.
authors.affiliation: Institute of Intelligent Structure and System, School of Electronics & Information Engineering, Soochow University, Suzhou 215006, P. R. China. lei_li56@163.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Wenshi
authors.initials: W
authors.lastname: Li
authors.forename: Aimin
authors.initials: A
authors.lastname: Ji
authors.forename: Ziou
authors.initials: Z
authors.lastname: Wang
authors.forename: Canyan
authors.initials: C
authors.lastname: Zhu
authors.forename: Lijun
authors.initials: L
authors.lastname: Zhang
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Yang
authors.forename: Ling-Feng
authors.initials: LF
authors.lastname: Mao