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Summary
Graphene, the two-dimensional honeycomb carbon lattice isolated in 2004, has enabled significant advancement in a variety of subfields in physics due to its extraordinary electronic properties. Among those properties is the ability to sustain the quantum Hall effect with more relaxed experimental conditions that traditional semiconductors. Our role within NIST’s core mission is to advance trust in electrical measurements, by using cutting-edge quantum electrical devices that become definitive U.S. standards. Our mission also drives us to disseminate those end-user-friendly standards throughout the nation. Our wide-ranging efforts include: applied research to expand device functionality and to solidify foundations of our calibration services, and executive plans to transfer knowledge, intellectual property, and technology to partners within the U.S. Government and private industry. We have utilized graphene to dramatically improve metrology based on the fundamental constants, becoming the first Nation to use it for the dissemination of an electrical unit (ohm).
Description
The quantum Hall effect (QHE), and devices that exhibit it, will continue to serve as the foundation of the ohm while also expanding its territory into other SI derived units. The world adopted the quantum SI in 2019, and it remains essential that the global metrology community pushes forth and continues to innovate and produce new technologies for disseminating the ohm and other electrical units.
For electrical standards, considerations must be made regarding two important factors in metrology: simplicity of operation and total accessible parameter space. In the case of GaAs, the required infrastructure to achieve well-quantized resistances is demanding compared to using epitaxially grown graphene on SiC. It has been established that graphene-based QHE devices can exhibit a distinct advantage over GaAs-based devices when attempting to use low magnetic fields, higher temperatures, and larger currents. Improvement of devices to expand accessibility is expected to correlate with the reduction in cost and complexity of quantized Hall resistance (QHR) standards for metrology as well as any associated laboratory measurement apparatus.
For a few years, epitaxial graphene has been used as part of the electrical resistance dissemination service in the United States. The preceding years were primarily dedicated to optimizing the technology and fabrication processes so that graphene-based QHR devices could be deployed into U.S. and global industries. We at NIST are currently expanding SI traceability beyond the usual single value obtained with the QHE by developing graphene array devices and configurations that leverage mathematical star-mesh transformations. These devices would reduce dependency on artifact standards that are prone to time-dependent changes.
Enhanced and straightforward traceability to the QHR is one of the goals of the project, especially to assist customers who use room-temperature measurement systems. Another major goal of the project is to expand accessibility to more orders of magnitude of the ohm using graphene-based array and star-mesh devices, which, as mentioned above, provide multiple quantized resistance values. Furthermore, the project looks to expand the utility of graphene-based devices in efforts to create a quantized current source.
Major Accomplishments
- Gold Medal received by the U.S. Department of Commerce in 2025 (along with the Metrology of the Ohm project) for this pioneering work
- Device technologies have resulted in two issued patents
- Epitaxial growth for homogeneous graphene achieved at the centimeter scale
- Successful fabrication of star-mesh transformation devices with quantized resistance values up to 1 GΩ
REFERENCES of recent Major Accomplishments:
Recursive Star-Mesh Transformations for Resistance Standards
September 20, 2024
Author(s)
Dean G. Jarrett, Albert Rigosi, Dominick Scaletta, Ngoc Thanh Mai Tran, Heather Hill, Alireza Panna, Cheng Hsueh Yang, Yanfei Yang, Randolph Elmquist, David B. Newell
Optimization of Wye-D-Type Quantum Hall Resistance Standard
August 30, 2024
Author(s)
Yanfei Yang, Dean G. Jarrett, Alireza Panna, Albert Rigosi, David B. Newell, Randolph Elmquist, Cheng Hsueh Yang, Ngoc Thanh Mai Tran
Theoretically wye-delta transformation can be used to realize ultra-high resistances up to PΩ. For graphene-based quantum Hall array resistance standards fabricated to utilize the wye-delta transformation, a few challenges present themselves, including the
Direct insulator-relativistic quantum Hall transition in graphene
November 3, 2023
Author(s)
Pin-Chi Liao, Ching-Chen Yeh, Dinesh Patel, Wei-Chen Lin, Siang-Chi Wang, Albert Rigosi, Randolph Elmquist, Chi-Te Liang
Mathematical optimization of graphene-based quantized Hall arrays for recursive star-mesh transformations
October 9, 2023
Author(s)
Dominick Scaletta, Swapnil Mhatre, Ngoc Thanh Mai Tran, Cheng Hsueh Yang, Heather Hill, Yanfei Yang, Linli Meng, Alireza Panna, Shamith Payagala, Randolph Elmquist, Dean G. Jarrett, David B. Newell, Albert Rigosi
Graphene-Based Star-Mesh Resistance Networks
July 12, 2023
Author(s)
Dean G. Jarrett, Ching-Chen Yeh, Shamith Payagala, Alireza Panna, Yanfei Yang, Linli Meng, Swapnil Mhatre, Ngoc Thanh Mai Tran, Heather Hill, Dipanjan Saha, Randolph Elmquist, David B. Newell, Albert Rigosi
Variable Strain in Armchair and Zigzag Epitaxial Graphene Nanoribbons
March 20, 2023
Author(s)
Heather Hill, Ching-Chen Yeh, Swapnil Mhatre, Ngoc Thanh Mai Tran, Hanbyul Jin, Adam Biacchi, Chi-Te Liang, Angela R. Hight Walker, Albert Rigosi
Quantitative characterization of epitaxial graphene for the application of quantum Hall resistance standard
December 12, 2022
Author(s)
Linli Meng, Alireza Panna, Swapnil Mhatre, Albert Rigosi, Shamith Payagala, Dipanjan Saha, Ngoc Thanh Mai Tran, Ching-Chen Yeh, Randolph Elmquist, Angela R. Hight Walker, Dean G. Jarrett, David B. Newell, Yanfei Yang
A Macroscopic Mass From Quantum Behavior In An Integrated Approach
December 10, 2022
Author(s)
Frank Seifert, Alireza Panna, Lorenz Keck, Leon Chao, Shamith Payagala, Dean G. Jarrett, Dipanjan Saha, Randolph Elmquist, Stephan Schlamminger, Albert Rigosi, David B. Newell, Darine El Haddad
The revision of the International System of Units (SI) on May 20th, 2019, has enabled new improved experiments to consolidate and simplify electrical and mechanical metrology currently underway. Historically within the SI, the definition of energy was only
Progress of Quantum Hall Research for Disseminating the Redefined SI
November 19, 2022
Author(s)
Albert Rigosi, Mattias Kruskopf, Alireza Panna, Shamith Payagala, Dean G. Jarrett, Randolph Elmquist, David B. Newell
Versatility of uniformly doped graphene quantum Hall arrays in series
August 8, 2022
Author(s)
Ngoc Thanh Mai Tran, Swapnil Mhatre, Heather Hill, Ching-Chen Yeh, Dipanjan Saha, David B. Newell, Angela R. Hight Walker, Chi-Te Liang, Randolph Elmquist, Albert Rigosi
Desorption timescales on epitaxial graphene via Fermi level shifting and Reststrahlen monitoring
July 10, 2022
Author(s)
Ngoc Thanh Mai Tran, Swapnil Mhatre, Cristiane Santos, Adam Biacchi, Mathew Kelley, Heather Hill, Dipanjan Saha, Chi-Te Liang, Randolph Elmquist, David B. Newell, Benoit Hackens, Christina Hacker, Albert Rigosi