Effects of long-range interactions in metal epitaxial growth

Abstract

The van der Waals constant ${C}_{3}$ describing the long-range attractive interaction between a Cu atom and a Cu(100) surface is calculated, along with the dominant correction ${z}_{0}$ for the shift in the reference plane, using expressions derived by Persson and Zaremba which take into account the optical response of Cu. The result ${C}_{3}\ensuremath{\simeq}2.1\mathrm{eV}{\mathrm{\AA{}}}^{3}$ is significantly smaller than predicted by a simple Lennard-Jones (LJ) Cu potential used in recent simulations, but large enough to explain experimental observations of a significant increase in mound angle in Cu/Cu(100) growth for large angles of incidence. In contrast, trajectory calculations indicate that the LJ Cu potential appears to overestimate the effects of long-range attraction. Our results also indicate that for small angles of incidence $(\ensuremath{\theta}<50\ifmmode^\circ\else\textdegree\fi{}),$ the dominant effects of attraction on the surface morphology in Cu/Cu(100) growth are related to the short-range rather than to the long-range interaction. Similar results are presented for Ag/Ag(100).