Modelling of transition and noble metal vicinal surfaces: energetics, vibrations andstability

Abstract

The energetics of transition and noble metal (Rh, Pd, Cu) vicinal surfaces, i.e.,the surface energy, step energy, kink energy and electronic interactions betweensteps, is studied at 0 K from electronic structure calculations in the tight bindingapproximation using an s, p and d valence orbital basis set. Then, the surfacephonon spectra of copper are investigated in the harmonic approximation with thehelp of a semi-empirical inter-atomic potential. This allows one to derive thecontribution of phonons at finite temperatures to the step free energy and to theinteractions between steps. The last part is devoted to the stability of vicinalsurfaces relative to faceting with special attention paid to the domain of orientations(100)–(111). Semi-empirical potentials are shown to be not realistic enough to give areliable answer for this problem. The results derived from electronic structurecalculations predict a variety of behaviours and, in particular, a possible facetinginto two other vicinal orientations. Finally, temperature effects are discussed.Comparisons are made with other theoretical works and available experiments.