Four-port AC quantized Hall resistance measurements

We report four-port measurements of quantized Hall resistances (QHRs) over the frequency range of 200 Hz to 2000 kHz. The importance of capacitive current flow from the conducting layer of the QHR device is illustrated by effectively reversing the polarity of the potentials of a split guard layer in close proximity to the QHR device. The frequency dependence of the current coefficients of the quantized Hall resistances have been investigated.