Regular visitors to HANNOVER MESSE will know that increasing miniaturization in electronics is set to produce components that consist of only a few or even singular molecules. Linking these components at nano level to an electrical circuit will call for tiny wires like those that the international research team from the CAU and the Donostia International Physics Center are creating from a single molecule. The wires in question are just two atomic bonds long and one atom wide. If that’s not amazing enough in itself, the scientists have just discovered that these molecular wires can also regulate the current!

In other words, they work like a nano power switch, which will make them useful in electronic components at nano scale in the future. "This is the simplest molecular wire imaginable - thinner and much shorter is not possible," the Kiel physicist Torben Jasper-Tönnies explains. Just as with larger circuits, both ends of this nano wire must be connected to a metal electrode so as to measure the flow of current. However, there are no metal clips small enough to create electrical contacts at this scale. "Electrically contacting individual molecules in a nano circuit is a problem that has not yet been resolved satisfactorily and is widely discussed in the research community, Jasper-Tönnies says. He points out that the scientists developed a new wire consisting of only a single molecule so as to enable an electrical contact, adding: “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." The research team used a scanning tunneling microscope (STM) to create the second contact required.

During the measurements they were able to conduct this way, the researchers also found that quantum mechanical forces act between the metal tip of the STM and the nano wire, which can be used to bend the wire mechanically. The striking effect is that the current is reduced if the wire is only slightly bent, but increases if there is a strong bend. As Jasper-Tönnies explains, "By bending the wire, we were able to switch the current on or off. Although our wire is so simple, it behaves in a very complex way, which surprised us!"

In other words, they work like a nano power switch, which will make them useful in electronic components at nano scale in the future. "This is the simplest molecular wire imaginable - thinner and much shorter is not possible," the Kiel physicist Torben Jasper-Tönnies explains. Just as with larger circuits, both ends of this nano wire must be connected to a metal electrode so as to measure the flow of current. However, there are no metal clips small enough to create electrical contacts at this scale. "Electrically contacting individual molecules in a nano circuit is a problem that has not yet been resolved satisfactorily and is widely discussed in the research community," Jasper-Tönnies says. He points out that the scientists developed a new wire consisting of only a single molecule so as to enable an electrical contact, adding: "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." The research team used a scanning tunneling microscope (STM) to create the second contact required.

During the measurements they were able to conduct this way, the researchers also found that quantum mechanical forces act between the metal tip of the STM and the nano wire, which can be used to bend the wire mechanically. The striking effect is that the current is reduced if the wire is only slightly bent, but increases if there is a strong bend. As Jasper-Tönnies explains, "By bending the wire, we were able to switch the current on or off. Although our wire is so simple, it behaves in a very complex way, which surprised us!"