Expansion of Graphene-Based Device Technology for Resistance Metrology

TL;DR

This paper discusses advancements in graphene-based quantum Hall resistance devices, focusing on expanding their operational parameters beyond the standard $ u=2$ plateau for improved resistance metrology standards.

Contribution

It explores the potential of using higher Landau levels in graphene for resistance standards, addressing challenges in precision compared to the $ u=2$ plateau.

Findings

EG-based QHR devices established as national standards

Higher Landau levels in graphene currently lack the precision of the $ u=2$ plateau

Research directions include increasing the parameter space for resistance standards

Abstract

The field of Quantum Hall metrology had a strong start with the implemntation of GaAs-based devices, given that 2D materials systems provided access to interesting quantum phenomena, including the infrastructure associated with making relevant measurements. With the technology laid out, further improvements in both infrastructure and standards were achieved in the previous two decades as EG-based quantized Hall resistance (QHR) devices became established as national standards. Since the metrology community has reached some understanding that a comparison against GaAs-based QHR devices had been accomplished, the next steps became clearer as far as how the EG-based QHR with a single Hall bar could be further developed. Since the early 90s, it has been of modest interest that QHR devices have a means of interconnecting several single Hall bar elements and has since been a subject of research. NMIs are now presently at a juncture where consideration must be granted beyond just simplicity of operation. A natural direction for resistance standards would be to increase the total accessible parameter space. This means using EG-based QHR devices to output more than the single value at the $\nu = 2$ plateau (about 12.9 k$\Omega$). A first natural question is whether one may use the $\nu = 6$ plateau or $\nu = 10$ plateau, and though some work has been done with these Landau levels in graphene, they simply do not offer the same level of precision as the $\nu = 2$ plateau.