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 t riple. A many-body, semi-empirical potential derived from tight-bindin g models is used. The step energy and the step-step interaction are de duced. The energy of multiple steps is found to be roughly proportiona l to the step height, except for vicinals of (111) with (111)-type ste p edges. On Cu(115) the energy for displacing a single step is found t o be very small. As a general rule, the energy of perturbed configurat ions cannot be deduced from the surface energy of macroscopic facets.