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SUMMARY:“Fast controlled single-electron transport in a quantum dot elec
 tron pump” - Dr Stephen Giblin  National Physical Laboratory\, Teddingto
 n\, UK
DTSTART:20121022T131500Z
DTEND:20121022T141500Z
UID:TALK41221@talks.cam.ac.uk
CONTACT:Kimberly Cole
DESCRIPTION:Electron pumps transport an integer number of electrons betwee
 n source and drain leads in response to a periodic control voltage. Even b
 efore the first demonstration of metallic electron pumps in the early 1990
 s\, pumps were mooted as a new way of defining the ampere\, the unit of el
 ectric current and one of the seven base units in the SI system. \n\nThis 
 talk will briefly review historical efforts to realise accurate electron p
 umps before focussing on the recent work of a NPL-Cambridge collaboration\
 , which demonstrated 1 part-per-million accuracy in a quantum dot pump clo
 cked at 945 MHz [1]. This record combination of speed and accuracy was mad
 e possible by driving the pump with a specially designed waveform. Prospec
 ts for improving the accuracy will be discussed\, in the context of the li
 kely future re-definition of the SI unit ampere in terms of a fixed value 
 of the electron charge.\n\n[1] S. P. Giblin et al.\, Towards a quantum rep
 resentation of the ampere using single electron pumps\, Nature Communicati
 ons  3 (930) (2012)\n
LOCATION:Mott Seminar Room\, Cavendish Laboratory\, Department of Physics
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