Uncovering Compounds by Synergy of Cluster Expansion and High-Throughput Methods

摘要

Predicting from first-principles calculations whether mixed metallic elements phase-separate ornform ordered structures is a major challenge of current materials research. It can be partially addressed inncases where experiments suggest the underlying lattice is conserved, using cluster expansion (CE) and anvariety of exhaustive evaluation or genetic search algorithms. Evolutionary algorithms have been recentlynintroduced to search for stable off-lattice structures at fixed mixture compositions. The general off-latticenproblem is still unsolved. We present an integrated approach of CE and high-throughput ab initio calculationsn(HT) applicable to the full range of compositions in binary systems where the constituent elements or thenintermediate ordered structures have different lattice types. The HT method replaces the search algorithmsnby direct calculation of a moderate number of naturally occurring prototypes representing all crystal systemsnand guides CE calculations of derivative structures. This synergy achieves the precision of the CE and thenguiding strengths of the HT. Its application to poorly characterized binary Hf systems, believed to be phaseseparating,ndefines three classes of alloys where CE and HT complement each other to uncover newnordered structures.