Cleavage of rutile SiO2 hemi-crystals: Insights from first-principles investigations

In the current study, less-explored low-index surfaces of rutile-like SiO2 have been examined through first-principles electronic structure calculations. This work reports on the surface energies of the (110), (100), (101) and (001) facets of high-pressure SiO2 polymorph, also referred to stishovite. Surface induced atomic displacements with respect to bulk were computed using a periodic slab approach. A multitude of density functional approximations, both dispersion-free and dispersion-corrected, were applied to perform the necessary calculations. Anomalously, the (100) plane was discovered to be the most energetically favorable low-index facet. It also turned out that the (001) was the least stable cut. In addition, the level of agreement between our computed surface energies and atomic shifts for rutile SiO2(110) and the results of the investigation prior to the present work was found to be acceptable. (C) 2017 Elsevier Masson SAS. All rights reserved.