Crystal Structure Search based on Evolutionary Algorithm Combined with First-principles Calculation

Abstract

It should be not too much to say that crystal structure determines the various properties of material. However, crystal structure prediction before synthesis experiment has been the fundamental challenge in the field of materials science. Its difficulty originates in the infinite possibility of the crystal structure, including combinations of atomic positions, lattice constants and chemical composition. Although number of global optimization method has been proposed to overcome this difficulty, it is very recent that we can predict stable crystal structure only from chemical composition, thanks to the sophisticated state of art, evolutionary algorithm. In this paper, we will briefly introduce the application procedure of evolutionary algorithm to the crystal structure search to predict the stable crystal structure. By utilizing evolutionary algorithm combined with first-principles calculation, we successfully obtained crystal structures of high-pressure phase of KNbO₃ and SrZnO₂. Applicability of present method will be demonstrated by introducing two example cases, and further analysis will be shown to quantify the diversity of population and correlation between generated structures.