Switches use single atoms
A researcher in the Netherlands has developed switches whose mechanical contacts consist of single atoms and whose working part consists of a single molecule.
Marius Trouwborst, working in the University of Groningen, has been working with fine gold wires. First, a wire is attached to a strip of flexible plastic and carefully bent so as to stretch the wire. Just before it breaks, the wire has a diameter of one atom. The ends are then pulled apart and pushed together again. Every time the wire breaks, the atoms in the ends become organised differently, until they take the form of pyramids with a single atom at the apex. By moving the two ends back and forth over 0.1nm, the switch can be turned on and off.
In the presence of hydrogen gas, a single molecule can be caught between the tips. When an electrical voltage is imposed across the gap, the current passes through the molecule. If the voltage is increased, the hydrogen molecule starts to vibrate, and the resistance suddenly drops.
Trouwborst receives his PhD on January 30th 2009, but he has already started work at the IBM Zurich Research Laboratory in Switzerland.
