Improved AC quantized Hall measurements

Abstract

AC quantized Hall resistance (QHR) measurements have been performed with an improved probe and sample mounting system. We describe investigations of the structure of the R/sub H/ plateau for a range of sample currents and temperatures, and for different wiring configurations. We have observed R/sub xx/ minima smaller than 0.02/spl times/10/sup -6/ of R/sub H/, an order of magnitude smaller than most published values.