Exploring Interfacial Reconstructions by adapting the Minima Hopping Method

While advances have been made in crystal structure prediction, there have been limited attempts at predicting interfacial structure. The Minima Hopping Method (MHM) is a structure prediction method that uses short molecular dynamics escape trials to explore a potential energy landscape, and a fingerprinting approach to avoid previously visited minima. The MHM has been successfully employed in studying molecular clusters, bulk solids, and surfaces. In this work, we extend the MHM to search for low-energy structures at solid-solid interfaces. We use as a test system non-stoichiometric grain boundaries in strontium titanate (SrTiO₃), which have been studied twice previously in efforts to predict interfacial structure. For each non-stoichiometric grain boundary considered, our MHM approach is able to predict lower energy structures than previously reported. Our method is simple to generalize to other interfacial systems and may be used with empirical potentials as well as density functional theory to explore feature-rich interfacial potential energy landscapes.