Step interactions and surface stability for Cu vicinals

The surface energies are computed for vicinals of Cu(100), Cu(110) and Cu(111) using a molecular dynamics technique modified to minimize the surface energy at zero temperature. The steps are simple, double or triple. A many-body, semi-empirical potential derived from tight-binding models is used. The step energy and the step-step interaction are deduced. The energy of multiple steps is found to be roughly proportional to the step height, except for vicinals of (111) with (111)-type step edges. On Cu(115) the energy for displacing a single step is found to be very small. As a general rule, the energy of perturbed configurations cannot be deduced from the surface energy of macroscopic facets.