Structural stability of atomic environment types in AB intermetallic compounds

A simple model is presented for studying the structural stability of atomic environments of AB intermetallic compounds. The relative stability of the four most common atomic environment types (AETs) has been systematically calculated within a tight-binding model. The calculated three-dimensional structure map using the difference of the valence electron orbital energy of an atom, AE, the distance between atoms, d, and the average number of electron per atoms, N, shows good agreement with the corresponding semi-empirical quantum structural diagram (QSD). This three-dimensional structure map is for the global understanding of structural trends shown in d versus ΔE plots at constant N̄_v (with constant power indexes λ of the repulsive potential term) and in ΔE versus N̄ plots at constant d and λ. The approach used in this paper provides a possibility of classifying intermetallic compounds into AET with systematical tight-binding calculation by extending to different kind of interaction systems, which might be taken as one step towards setting up a knowledge base of crystal structure prediction for materials design.