Comparison of 1 MΩ Graphene Quantum Hall Arrays Based on Wye-Delta Transformation

Utilization of the wye-delta transformation significantly reduces the number of Hall bars in quantum Hall array devices for high resistances above 1 MΩ, improving the yield of fabrication. We fabricated two types of wye-delta quantum Hall array devices that produce near 1 MΩ resistance, each consisting of 28 and 18 Hall bars, respectively. In this work, we report the measurement results of the 28-element quantum Hall arrays using a dual-source bridge (DSB) and two 1 MΩ standard resistors. This indirect comparison shows that two identical arrays are quantized at 77h2e2(≈1MΩ) to within 60 nΩ/Ω at magnetic fields of 5 T and 6 T. We will use the DSB to perform the direct comparison of two 18-element arrays without the 1 MΩ standard resistors in the coming months.