Quantum resistance metrology in graphene

TL;DR

This study demonstrates that graphene exhibits quantum Hall resistance quantization comparable to traditional semiconductors, with potential for precise resistance metrology despite current experimental limitations.

Contribution

It provides the first detailed metrological characterization of quantum Hall resistance in graphene, confirming its suitability for resistance standards.

Findings

Quantum Hall resistance in graphene matches conventional semiconductors within 15 ppm.

Longitudinal resistivity vanishes within measurement noise up to 2 μA.

Contact resistance limits measurement precision and induces heating.

Abstract

We have performed a metrological characterization of the quantum Hall resistance in a 1 $\mu$m wide graphene Hall-bar. The longitudinal resistivity in the center of the $\nu=\pm 2$ quantum Hall plateaus vanishes within the measurement noise of 20 m$\Omega$ upto 2 $\mu$A. Our results show that the quantization of these plateaus is within the experimental uncertainty (15 ppm for 1.5$ \mu$A current) equal to that in conventional semiconductors. The principal limitation of the present experiments are the relatively high contact resistances in the quantum Hall regime, leading to a significantly increased noise across the voltage contacts and a heating of the sample when a high current is applied.