INDIVIDUAL electrons have been observed in a flowing current for the first time.
Current is usually measured indirectly, for example by detecting the drop in voltage across a resistor. Now, a team from Chalmers University of Technology in Gothenburg, Sweden, has successfully counted each electron in a current after getting them to line up in single file.
To do this, they used an array of 50 microscopic, superconducting electrodes separated by gaps a micron across. The set-up was cooled to 30 millikelvin and a voltage applied across the array. At that temperature, the individual electrons tunnelled through the array from…
