A first-principles and mesoscopic model analysis for pair, trio, and quarto interactions of Au adatoms on Ag(100)

Abstract

The first-principles density functional theory (DFT) method is used to directly calculate the short- and medium-range pair, trio, and quarto interactions of Au atoms in Ag(100)-supported and freestanding (unsupported) Au dimers, trimers, and tetramers. This allows us to systematically investigate the substrate effects. We find that the interactions for freestanding Au clusters have striking differences from their Ag(100)-supported counterparts, especially for shorter-range interactions. This reflects the strong substrate effects on these pair, trio, and quarto interactions. We also find that, for these Ag(100)-supported two-dimensional Au clusters, the substrate-mediated interactions obtained from an elastic eigenvector approach including a mesoscopic interacting range (called the mesoscopic model) have reasonable agreement with the DFT results.