Atomistic structure of high-index surfaces in metals and alloys

Interatomic potentials of the embedded atom (EAM) type were used to study the atomistic structure of high-index surfaces in metals and ordered alloys. The results show that a structural unit model can be developed for the structure of the high-index surfaces on the basis of the structure of a few low-energy surfaces. The model can predict the structural features and also give an estimate of the energies of the higher-index surfaces. We present examples in pure metals, Fe and Al and in the intermetallic alloys FeAl, NiAl and TiAl. The energies of alloy surfaces that present different possible terminations depend on the composition of the bulk. We show that this effect can be significant for low-index surfaces, and decreases in magnitude for higher-index surfaces. (C) 1998 Elsevier Science B.V. All rights reserved.