Density functional theory calculations of the surface structure of the inverse spinel zinc orthotitanate

摘要

We present an examination of many different surface terminations of Zn2TiO4 (ZTO) obtained by density functional theory calculations. We have examined a total of 41 surface terminations generated from the {001}, {011}, and {111} families of surfaces. Termination of the anisotropic bulk structure of ZTO can produce asymmetric corrugated surfaces that possibly include surface termination artifacts. We have addressed this issue with surface 'smoothing' via atomic transposition of individual atoms across the slab. This procedure reduces the energy penalty associated with large geometric corrugations in the surface layer, particularly in the case of ZTO(111) surfaces. The interface with the lowest energy was found to be a termination of the ZTO(010) surface having a surface formation energy of 1.09 J m(-2). A moderately higher energy surface termination was found for the ZTO(110) surface. This ZTO(110) surface has a surface formation energy approximately 0.1 J m(-2) higher than that of the lowest energy ZTO(010) surface.