Quasidynamic computation of multilayer relaxations, repulsion between steps and kink formation energy on copper vicinal surfaces

Abstract

Multilayer relaxations, the kink formation energy, the repulsion between steps and surface energies are computed for (11 n) and (331) vicinal surfaces of copper using a quasidynamic minimization algorithm. We used two different models for the interatomic forces, A and B, which correspond respectively to the empirical Morse potential and to a N-body, semi-empirical potential derived from a simple tight binding scheme. The ability of these models to reproduce the temperature dependence of dynamical properties of copper is tested by comparing the computed atomic mean square displacements with available experimental data. Only model B reproduces satisfactorily the dynamical behavior of bulk copper at T ≠ 0 K: experimental and computed atomic mean square displacements are in excellent agreement. Further comparison with the experiment shows that model A leads to wrong surface relaxations and overestimates surface and kink formation energies, whereas good agreement is obtained for model B. Both models fail, however, to predict the correct repulsion energy between steps.