Solid and liquid junctions

Abstract

Atomic scale energetics, structure, and formation mechanisms of solid and liquid junctions occurring between a solid metal tip and a clean metal surface or between the tip and a liquid film of hexadecane molecules adsorbed on a solid surface, are investigated using large-scale molecular dynamics simulations. The solid intermetallic junctions exhibit crystalline structure and their elongation mechanism, upon slow retraction of the tip from the surface after contact, involves a sequence of plastic deformations and yield processes, coupled with structural rearrangements. The molecular liquid is layered in the capillary junction for small separations between the two confining solid surfaces. Further separation results in a transition to a liquid-like region in the middle of the elongated liquid column. Investigations of the molecular scale origins of capillary liquid junction formation, and of the Young-Laplace equation applied to nanoscale liquid junctions, as well as consequences of solid and liquid junction formation for force measurements via atomic force microscopy, are discussed.