Fantastic Metastable States and Where to Find Them: A Computational Search for Superlattices with Enhanced Functional Properties

Superlattice systems continue to be of great interest in the development of new or enhanced material functionalities. One exciting prospect is that the conditions of the superlattice allow for the stabilization of novel states not accessible in bulk materials. To find such states, and the conditions under which they are stabilized, we construct a database of first principles calculations which describe not only the ground state of each constituent material, but a number of local minima and how these states change with mechanical, electrical, and other conditions. A data-driven approach is used in structure determination where the most probable local minima are systematically identified through analysis of existing materials databases. The resulting data set can be used as input to the "bulk-layer model" [1] to rapidly identify superlattice combinations with desirable functional properties, as well as the superlattice "stacking method" [2] to carefully compute the ground state of a particular superlattice. Examples applying the method to perovskite oxide compounds and superlattices will be presented.

[1] https://arxiv.org/abs/1809.05168
[2] https://doi.org/10.1103/PhysRevB.89.214108