Evidence for universality of tunable-barrier electron pumps

Research output: Contribution to journalArticleScientificpeer-review


  • Stephen P. Giblin
  • Akira Fujiwara
  • Gento Yamahata
  • Myung-Ho Bae
  • Nam Kim
  • Alessandro Rossi
  • Mikko Mottonen
  • Masaya Kataoka

Research units

  • National Physical Laboratory
  • NTT Corporation
  • Korea Res Inst Stand & Sci, Korea Research Institute of Standards & Science (KRISS)
  • Univ Cambridge, University of Cambridge, Cavendish Lab


We review recent precision measurements on semiconductor tunable-barrier electron pumps operating in a ratchet mode. Seven studies on five different designs of pumps have reported measurements of the pump current with relative total uncertainties around 10(-6) or less. Combined with theoretical models of electron capture by the pumps, these experimental data exhibits encouraging evidence that the pumps operate according to a universal mechanism, independent of the details of device design. Evidence for robustness of the pump current against changes in the control parameters is at a more preliminary stage, but also encouraging, with two studies reporting robustness of the pump current against three or more parameters in the range of similar to 5 x 10(-7) to similar to 2 x 10(-6). This review highlights the need for an agreed protocol for tuning the electron pump for optimal operation, as well as more rigorous evaluations of the robustness in a wide range of pump designs.


Original languageEnglish
Article number044004
Pages (from-to)1-17
Number of pages17
Issue number4
Publication statusPublished - Aug 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • electron pumps, primary electrical metrology, current standards, current measurement, CAPACITANCE STANDARD, ACCURACY, CURRENTS

ID: 35822569