Electron Counting Capacitance Standard with an improved five-junction R-pump

The Electron Counting Capacitance Standard currently pursued at PTB aims to close the Quantum Metrological Triangle with a final precision of a few parts in 10^7. This paper reports the considerable progress recently achieved with a new generation of single-electron tunnelling devices. A five-junction R-pump was operated with a relative charge transfer error of five electrons in 10^7, and was used to successfully perform single-electron charging of a cryogenic capacitor. The preliminary result for the single-electron charge quantum has an uncertainty of less than two parts in 10^6 and is consistent with the value of the elementary charge.Comment: 16 pages, 9 figures, 1 tabl

Quantum Metrology Triangle Experiments: A Status Review

Quantum Metrology Triangle experiments combine three quantum electrical effects (the Josephson effect, the quantum Hall effect and the single-electron transport effect) used in metrology. These experiments allow important fundamental consistency tests on the validity of commonly assumed relations between fundamental constants of nature and the quantum electrical effects. This paper reviews the history, results and the present status and perspectives of Quantum Metrology Triangle experiments. It also reflects on the possible implications of results for the knowledge on fundamental constants and the quantum electrical effects.Comment: 36 pages, 8 figure

Introducing Joint Research Project «Quantum Ampere» for the realisation of the new SI ampere

The metrology community lately has adopted the long-term aim of basing the SI unit system on fundamental constants of nature. The base electrical unit, the ampere, will then be re-defined in terms of a fixed value of the elementary charge e. The most direct realization of the new ampere definition requires controlling the number of electrons which flow in a unit time interval, and of counting the errors occurring in this process of clocking single electrons. State of the art nanofabrication technology allows the fabrication of single-electron transport devices - known as single-electron pumps - which generate electric current by moving electrons one at a time. These devices are capable of delivering currents of about 100 pA with an accuracy at the 1 part per million level. Also, ultrasensitive single-electron detectors have been explored that allow electric charge detection on a resolution level below e. The European Joint Research Project presented here, undertaken by a consortium of several research institutes, aims at further developing the best existing concepts of single-electron pumps and to combine them with single-electron detectors for creating highly accurate quantum current sources, to be used as future current standards. Furthermore, necessary current measurement instrumentation will be developed. The paper comprises the project aims and the main results achieved so far