Single‐atom point contact devices fabricated with an atomic force microscope

The fabrication of atomic point contacts by using anodic oxidation of thin Al films with an atomic force microscope is reported. In situ electrical measurements were used as feedback to control the fabrication of Al nanowires that were subsequently anodized through their cross section to form point contacts. When the conductance of a point contact is reduced below ∼5×10−4 S it starts to decrease in discrete steps of ∼2e2/h. In some devices we are able to stabilize the conductance at a value near 2e2/h which corresponds to a single, atomic‐sized conducting channel.