New approaches to study of mismatched interfaces structure on low-index surfaces by molecular dynamics simulation

A Hassani and A Khmich and A Hasnaoui, APPLIED SURFACE SCIENCE, 623, 157072 (2023).

DOI: 10.1016/j.apsusc.2023.157072

We used molecular dynamics simulations to study the structure of mismatched Al/Ni and Ag/Cu interfaces, considering low-index surfaces of the substrate. Embedded Atom Potentials are being employed to mimic atomic interactions between the different elements. The effect of the substrate orientation on the adlayer structure is investigated. The results showed that, on the (1 1 1) substrate, the adlayer presents a coincidence site lattice characterized by a rotation (labeled alpha) with respect to the substrate. This coincidence site lattice may contain dislocations and twin boundary that can be produced by the occurrence of a twin spirals (with opposite directions). To accommodate the adlayer deposition on the substrate, a slight shuffling of some atoms occurs in the substrate and leads to a rectangular structures producing a dislocation. Furthermore, on the (001) substrate, the accommodation of the triangular structure on the square lattice (substrate) is produced by a shift of some atomic rows producing a dislocation. But, the agglomeration of several square structures of 2d shape gives rise to a polycrystal delimited by a disclination forming grain boundaries and vacancies. However, the inward adsorption on the (1 1 0) substrate restricts the space of extension of adsorbed atoms, producing linear cracks. The relaxation of atoms adsorbed on these cracks change the linear shape of vacancies towards a staircase structure.

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