The Quantum Hall Effect and Resistance Standards

Abstract

Following the discovery of the quantum Hall effect in 1980 metrologists were eager to develop the effect as a resistance standard in a similar manner to the development, a decade earlier, of the Josephson effects in superconductors as a voltage standard. This article reviews the progress made by many national laboratories to assess and compare the quality and limitations of semiconductor devices, mainly silicon MOSFETs and GaAs/AlGaAs heterostructures, as quantized Hall resistance standards with values RH (i) = RK/i = h/ie2, where RK = 25812,807 Ω is the von Klitzing constant and i is an integer. Potentiometric and cryogenic current comparator bridge techniques for the measurement of RK in terms of conventional resistance standards with 1 σ relative accuracies better than 1 part in 108 are compared, and determinations of RK in ohms with accuracies as high as 2,4 parts in 108 using calculable capacitors are described. The comparison of direct determinations of RK with alternative derivations of h/e2 leading to the CCE recommendations and subsequent international adoption, from 1 January 1990, of the value 25812,807 ± 0,005 Ω for RK are also described.