Structure and evolution of a metallic nanowire-tip junction

We discuss the stability and evolution of metallic nanowires attached to tips. Using surface energy arguments we show that the junction between tip and wire will occupy only a small fraction of the total length of the wire. explaining why perfect wire segments can show up in experiment. Energetic arguments can also be used to understand the observed preferential stability of gold wires grown along the [110] direction. The thinning process of an fcc [110] wire at finite temperature is found by Monte Carlo simulation to occur slowly and laver by layer, as opposed to [ 100] and [111] wires that are unstable and quickly destroy themselves. We finally analyze the way in which "weird" tubular wires, highly ordered but noncrystalline, attach to, and can be pulled from, crystalline wires or tips. A mechanism based on tension-induced dislocation delocalization, that appears to be important in the process of wire uncoiling from a tip or from a thicker wire, is identified.