World's Most Accurate Electron Pump Made

Category: Science & Technology
Posted: July 11, 2012 09:18AM
Author: Guest_Jim_*

Standardization of metrics is an important thing for any civilization to achieve, for both scientific matters and trade purposes. This is why the precise platinum shapes being held in France are being replaced by more exact measures of units. Already the meter and second, to name two units, have been exactly defined, with groups around the world working to define the kilogram, and soon we may see the ampere get a fundamental definition, thanks to researchers at the National Physical Laboratory and University of Cambridge.

The researchers have successfully built an electron pump that is capable of moving individual electrons through a circuit one at a time as fast as one billion electrons per second. This was achieved with a special nanodevice that holds a quantum dot between two electrodes. The quantum dot first holds a great many electrons, but by increasing the energy of the dot, all but one of the electrons will back-tunnel out of the dot. This one electron is then ejected from the dot, into the desired circuit.

With one part-per-million accuracy, the researchers successfully created a 150 picoampere current. It may be a small current but could be a stepping stone to determine just how many electrons moving make up just one ampere, which is akin to determining the number of drops that make a river.

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