The increasing miniaturisation in electronics will result in components which consist of only a few molecules, or even just one molecule. An international research team from Kiel University (CAU) and the Donostia International Physics Center in San Sebastián/Spain, has developed a molecule integrating a wire with a diameter of only a single atom. They discovered that the current can be regulated via this molecular wire. It works like a nano power switch, and makes the use of molecular wires in electronic components at the nano scale feasible.

The wire produced by the scientists from Kiel and San Sebastián is just two atomic bonds long and one atom wide.

"This is the simplest molecular wire imaginable, thinner and much shorter is not possible," explained the Kiel physicist Torben Jasper-Tönnies, first author of the publication.

In order to measure the current flowing through the nano wire, both ends must be connected to a metal electrode - like with larger circuits. But there are no metal clips which are small enough to create electrical contacts at the nano scale.

"Electrically contacting individual molecules in a nano circuit is a problem that has not yet been solved satisfactorily, and is widely discussed in the research community," explained Jasper-Tönnies, who is writing his doctoral thesis in the working group of Professor Richard Berndt.

In order to enable an electrical contact, the scientists developed a new wire, consisting of only a single molecule.

"The special thing about our wire is that we can install it in a vertical position on a metal surface. This means that one of the two required contacts is already effectively built-in to the wire," explained Jasper-Tönnies.

To achieve this, the involved chemists used an approach from the Kiel Collaborative Research Centre (SFB) 677 “Function by Switching”. In the interdisciplinary research network, molecular platforms are among the areas of interest. The wire is attached to such a platform. It exhibits a high conductance, and can be easily attached to a metal surface like a suction cup - an electrical contact is realized