The findings of the researchers from institutes in Germany, France, Spain and Denmark were published in the latest issue of the prestigious magazine Physical Review Letters. A scanning tunnelling microscope (STM)
was used to construct an ultra small electrical circuit comprised of only two C60 molecules, each just 1 nanometer in diameter. The researchers first picked up a single C60 molecule with the STM
tip and thereafter approached a second molecule with a precision of a few trillionths of meters. During this controlled approach the physicists were able to measure the electrical current that flows between the two molecules. Understanding this current, which depends critically on the distance between the molecules, is important for utilizing molecules in future electronics.
The investigation revealed that the electrical current does not flow
easily between the two touching C60 molecules – the conductance is 100 times smaller than for a single molecule. This finding is crucial for future devices with closely packed molecules as it indicates that leakage currents between neighbouring circuits will be controllable.
These experimental findings are strongly supported by quantum-mechanical calculations which too come to the result of poor electrical conductivity between two C60 molecules.
The extreme precision of manipulation and control of single molecules
presented in this work open up a new route for exploring other
promising molecules. The deeper understanding of electrical current on the nanometer scale is an essential step towards novel molecular nanoelectronics.
Electron current through two C60-molecules which
are contacted with elec-trodes. As they are only one billionth of a
meter in diameter, ultra high precision is needed in order to control