A molecular dynamics study of Ni/Cu(001) interfaces

This work is focused mainly on the analysis of effects related to a lattice misfit at a metallic interface. The system studied is the Ni/Cu(0 0 1) which exhibits a misfit of 2.6%. For this structure, the adjustment between the lattice parameters of a Ni crystal layer over Cu(0 0 1) substrate is analysed. To avoid edge effects a large enough substrate is taken while the Ni crystal set on top has smaller dimensions than the substrate. We have studied structures of one, two, four and ten monolayers of Ni set on top of the Cu substrate. It is shown how the stabilisation of different interface structures on an atomic scale is achieved; especially, the type of processes that help to accomplish a gradual change in the atomic distances. The main conclusion is the anisotropy of the coupling provokes that a cubic becomes a tetragonal lattice. The rearrangement of atoms and the strain field induced by the coupling are studied in detail. (C) 2002 Elsevier Science B.V. All rights reserved.