Slab models of rutile TiO2 (110) surface: DFT and DFT+U calculations

Abstract

AbstractThe dependence of rutile TiO2 (1 1 0) surface's structural and electronic properties on the number of layers has been carefully investigated with DFT and DFT+Ud,p approaches using three slab models. We have found that oscillations of surface energy, electronic properties from DFT calculations on the three models are stronger than those from corresponding DFT+Ud,p calculations. The even‐odd fluctuations were demonstrated to relate to over delocalization of electrons, especially electrons in Ti 3d orbitals. The Ud,p corrections in DFT+Ud,p enabled to restrict the oscillations. The F2B slab model weakens the oscillations and calculations on F2B model quickly converge. However, the F2B model leads to artificial narrowness of band gap. Besides, when the number of layers increases, surface energy obtained from all three slab models approaches similar values. In particular, values of surface energy from DFT calculations converge to the experimental range for all three slab models.