Influence of voltage contacts on precision measurements of the quantized Hall resistance: an effect of externally injected current

The influence of the error voltage developed in a nonideal voltage contact by an externally injected current such as the offset current of a nanovolt meter in a four-terminal measurement of the quantized Hall resistance (QHR) has been analyzed, and it was found to be quite significant. Based on the analysis, we have provided some qualitative and even quantitative explanations for the previously reported experimental results by Jeckelmann and Jeanneret on the influence of the voltage contacts on the QHR [1997], which are not explained satisfactorily by the existing theories.