2019/01/31 by Stephen P. Giblin, Akira Fujiwara, Gento Yamahata +5 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall
paper · pdf · doi:10.1088/1681-7575/ab29a5
published as Metrologia vol. 56, 044004 (2019) · 18 pages, 8 figures
arxiv created 2019/04/23 · arxiv updated 2019/07/19
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 ∼ 5 × 10-7 to ∼ 2 × 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.