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Ab Initio Predictions of Double-Layer TiO₂-Terminated SrTiO₃(001) Surface Reconstructions C

Cook, Seyoung, Marks, Laurence D.
Journal of physical chemistry 2018 v.122 no.38 pp. 21991-21997
models, periodicity, physical chemistry, prediction, titanium dioxide
Predicting oxide surface structures, and surface structures in general, is a significant science frontier. Herein, we demonstrate an Ising model approach combined with density-functional calculations to predict several SrTiO₃(001) surface reconstructions. Constrained Ising tilings of TiO₅□ truncated octahedral units are used to construct the TiO₂ adlayers of SrTiO₃(001) surface reconstructions with TiO₂ double-layer terminations for a given periodicity and composition. This method is used to re-examine the (√5 × √5)R26.6° reconstruction and to predict several (√10 × √10)R18.4° reconstructions. The surface structures and energies of the newly predicted reconstructions, along with consideration of the previously reported (√13 × √13)R33.7°, 3 × 3, and (√2 × √2)R45.0° reconstructions, indicate that the larger, more complex TiO₂ double-layer SrTiO₃(001) reconstructions with lower coverages of the TiO₂ adlayer are made up of recurrent structural motifs represented by smaller, simpler reconstructions with higher coverages of the TiO₂ adlayer. These results demonstrate a route forward for predicting oxide and other surface structures using a relatively simple computational approach.