Implementation of a graphene quantum Hall effect Kelvin bridge for resistance calibration

We present here a first implementation and a preliminary validation of a Kelvin bridge based on the design proposed in [1] that allows the direct calibration of standard resistors operating at room temperature. The bridge is composed of a graphene quantum Hall array operating at a temperature of 1.6 K and a magnetic field of 9 T. The implemented bridge was employed to calibrate a standard resistor (NIST SP036) with a nominal value of 12906 Ω operating in a temperature-controlled oil bath at 25 °C. The result obtained from the calibration with the Kelvin bridge was compared with a calibration performed with a cryogenic current comparator against 100 Ω, in turn calibrated against a GaAs quantum Hall resistance standard. The relative deviation between the two results is at the level of with an uncertainty of a few parts in . The Kelvin bridge here presented can be integrated with other quantum Hall array resistance standards to calibrate standard resistors with decadal values.