A computational study of hcp Ti and Zr stepped surfaces

Abstract

The structure and energetics of ledge pairs (atomic steps) in surfaces (0001), (1010), (1210) of hcp Zr and Ti are studied by computer simulation using embedded-atom-type interatomic potentials. The configurations considered are the face to face, back to back, sequential, and double, according to their cross-sectional view. Ledge and kink formation and interaction energies are obtained. Vacancies and adatoms are introduced to study their formation and migration energies in interaction with the ledges. But for one case ( surface (1010) ) it is found that ledges are preferred sites for vacancy and adatom formation; also, their overall effect on diffusion is predicted to be small. The results indicate that the effect of ledges can be neglected beyond a few atomic distances