Shane Patel1 Maximilian Amsler1 Christopher Wolverton1

1, Northwestern University, Evanston, Illinois, United States

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 sampling previously visited minima [1] . 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 interfacial structures at solid-solid boundaries. We use as a test system non-stoichiometric grain boundaries in strontium titanate (SrTiO3), which have been the subject of previous structure prediction methods[2,3]. 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 both empirical potentials as well as density functional theory to explore feature-rich and complex interfacial potential energy landscapes. We will also illustrate applications of the minima hopping method to grain boundary structures in lithium-ion cathode materials.
This work was supported by the Center for Electrochemical Energy Science, an Energy Frontier Research Center funded by the US Department of Energy, Office of the Science, Basic Energy Science, award number DE-AC0206CH11.
[1] M. Amsler and S. Goedecker, The Journal of Chemical Physics, 133, 224104 (2010).
[2] A. L-S. Chua, N.A. Benedek, L. Chen, M.W. Finnis, and A.P. Sutton. Nature Materials, 9, 418, (2010).
[3] G. Schusteritsch and C.J. Pickard. Physical Review B. 90, 035424 (2014).