Ab initiocalculations of the atomic and electronic structure ofCaTiO3(001) and (011) surfaces

Abstract

We present the results of calculations of surface relaxations, energetics, and bonding properties for CaTiO3 (001) and (011) surfaces using a hybrid B3PW description of exchange and correlation. We consider both CaO and TiO2 terminations of the non-polar (001) surface, and Ca, TiO and O terminations of the polar (011) surface. On the (001) surfaces, we find that all upper-layer atoms relax inwards on the CaO-terminated surface, while outward relaxations of all atoms in the second layer are found for both terminations. For the TiO2-terminated (001) surface, the largest relaxations are on the second-layer atoms. The surface rumpling is much larger for the CaO-terminated than for the TiO2-terminated (001) surface, but their surface energies are quite similar at 0.94 eV and 1.13 eV respectively. In contrast, different terminations of the (011) CaTiO3 surface lead to very different surface energies of 1.86 eV, 1.91 eV, and 3.13 eV for the O-terminated, Ca-terminated, and TiO-terminated (011) surface respectively. Our results for surface energies contrast sharply with those of Zhang et al. [Phys. Rev. B 76, 115426 (2007)], where the authors found a rather different pattern of surface energies. We predict a considerable increase of the Ti-O chemical bond covalency near the (011) surface as compared both to the bulk and to the (001) surface.

Surface Relaxations, Surface Energies and Electronic Structures of BaSnO3 (001) Surfaces: Ab Initio Calculations

“…These results are in good qualitative agreement with other Ab initio calculations dealing with ABO 3 (001) surfaces. [11][12][13][14][26][27][28][29][30] In addition, the shrinkage in the interlayer distance, Dd 1-2 , of the SnO 2 -terminated surface is larger than that of the BaO-terminated surface, which disagrees with what happens in the case of the (001) surface. Moreover, it is shown that the amplitude of the surface rumpling on the SnO 2 -terminated surface of 3.742% is slightly larger than that of 3.348% for the BaO-terminated surface, …”

Structural and electronic properties of cubic KNbO3 (001) surfaces: A first-principles study

“…We present in Table 5 the calculated Mulliken effective charges Q and their changes Q with respect to the bulk values for atoms near the surface for the KO-and NbO 2 -terminated KNbO 3 (0 0 1) surfaces as described in Refs. [35,37]. The bond populations, and the relevant interatomic distances for KO-and NbO 2 -terminated KNbO 3 (0 0 1) surfaces are listed in Table 6.…”

Ab initio study of ATiO3 (001) surfaces

“…Layer Atom This work GGA [25] B3PW [26] This work LDA PW [13] B3PW [28] This work LDA PW [27] B3PW [28] AO Termination This work GGA [25] B3PW [26] This work LDA PW [13] B3PW [28] This work LDA PW [27] B3PW [28] AO the ith layer from the surface are expressed as z i :…”