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MM: Fachverband Metall- und Materialphysik

MM 18: Topical session: Integrated computational materials engineering for design of new materials IV

MM 18.1: Topical Talk

Dienstag, 8. März 2016, 10:15–10:45, H39

Robust crystal-structure prediction with structure maps — •Thomas Hammerschmidt — ICAMS, Ruhr-Universität Bochum, Bochum, Germany

The prediction of the crystal structure of a material from only its chemical composition is one of the key challenges in materials design. The most common strategies are (i) the search for the energetically most favourable crystal structure by explicit atomistic calculations and (ii) the identification of descriptors that allow extrapolations from known materials to unknown compounds. A promising approach of the second kind are structure maps that chart the bonding chemistry of known compounds. I will discuss two structure maps and motivate their descriptors that are based on physically intuitive functions of the number of valence electrons, the atomic volume and the electro-negativity. The first example, a structure map for complex intermetallic phases, is set up by electronic-structure considerations. This two-dimensional map correctly predicts the crystal structure of precipitates in multi-component Ni-base and Co-base superalloys. The second example is a three-dimensional structure map derived by a systematic cluster analysis of experimentally observed compounds of sp-block elements and transition metals. This map reaches a predictive power that is close to standard density-functional theory calculations. The identified descriptors remain valid for off-stoichiometric compounds and separate binary and ternary crystal-structure prototypes.