Nanoscale switches by rearrangement of single atoms

Conductance switching can be achieved by the displacement of single atoms in a reliable and fatigue-resistant two-terminal atomic switch - a nanoscale version of a transistor - reports a study published online this week in Nature Nanotechnology.

Miniaturization of electronic components to the nanoscale is driven by the need for faster, cheaper, less-power-consuming devices. In atomic-scale switches, the change in electrical conductance from the on to the off state relies on the control of the atomic configuration in a metal wire made up of a small number of atoms.

Elke Scheer and colleagues have created a switch that is made from an atomic-size aluminium contact that is located in the centre of a constriction fabricated in an aluminium wire. By passing high current through the constriction, single atoms are displaced by a phenomenon called electromigration, which changes the ability of the constriction to allow electrical current to pass through. The authors show a reproducible and reversible toggling of the conductance between two well-defined values due to the rearrangement of single atoms induced by electromigration. They also demonstrate the ability of the atomic switch to operate as a non-volatile memory device, showing that the switch can store one bit of information in its atomic configuration, which is written and read by means of an electrical current.