Current Transport at the Atomic Scale

Abstract Electrical contacts of the width of only one atom can be realized by the break‐junction technique. The conductance decreases stepwise due to structural reconfigurations when tearing a nano‐bridge in the few‐atom range. Transport is described by an ensemble of channels with possibly quite high transmission probabilities. For a single break‐junction the last one‐atom contact consists of a material‐specific channel ensemble, determined by the chemical valance as verified for quite a number of metals. d‐electrons in half‐metals and spin‐effects in magnetic materials will complicate this simple model. Break‐junctions also provide ideal contacts to investigate transport through freely suspended clusters or molecules like DNA.