Investigation of the stability of graphene devices for quantum resistance metrology at direct and alternating current

Interlaboratory comparisons of the quantized Hall resistance (QHR) are essential to verify the international coherence of primary impedance standards. Here, we report on the investigation of the stability of p-doped graphene-based QHR devices at direct and alternating currents at CMI, KRISS, and PTB. To improve the stability of the electronic transport properties of the polymer-encapsulated devices, they were shipped in an over-pressurized transport chamber. The agreement of the quantized resistance with R (K)/2 at direct current was on the order of 1 n omega omega(-1) between 3.5 and 7.5 T at a temperature of 4.2 K despite changes in the carrier density during the shipping of the devices. At alternating current, the quantized resistance was realized in a double-shielded graphene Hall device. Preliminary measurements with digital impedance bridges demonstrate the good reproducibility of the quantized resistance near the frequency of 1 kHz within 0.1 mu omega omega(-1) throughout the international delivery.

Automated summary

In this work, the stability of p-doped graphene-based QHR devices under both direct and alternating currents was investigated. Polymer-encapsulated devices were transported in an over-pressurized chamber to improve stability. The results showed that the quantized resistance remained consistent with the standard value at direct current, and good reproducibility was achieved at alternating current.