Metal-Insulator Transition in Stable One-Dimensional Arrangements of Single Gold Atoms

The atomic arrangement and conductance during the separation process of gold point contacts were simultaneously observed in situ by high-resolution transmission electron microscopy. One-dimensional arrangements of gold single atoms, i.e., atomic wires, appeared between two tips at the point contacts. They were stable when their length was increased up to 2.6 nm. The interatomic distance of the wires was 0.25–0.31 nm. It was found that metal-insulator transition occurs in the wires.