|Title||Graphene Devices for Tabletop and High-Current Quantized Hall Resistance Standards|
|Publication Type||Journal Article|
|Year of Publication||2019|
|Authors||A. F. Rigosi, A. R. Panna, S. U. Payagala, M. Kruskopf, M. E. Kraft, G. R. Jones, B-Y. Wu, H-Y. Lee, Y. Yang, J. Hu, D. G. Jarrett, D. B. Newell, and R. E. Elmquist|
|Journal||IEEE Trans. Instrum. Meas.|
|Type of Article||Article|
|Keywords||Binary cryogenic current comparator (BCCC), direct current comparator (DCC), Epitaxial graphene (EG), Metrology, quantized Hall resistance (QHR), standard resistor, standards and calibration|
We report the performance of a quantum Hall resistance standard based on epitaxial graphene maintained in a 5-T tabletop cryocooler system. This quantum resistance standard requires no liquid helium and can operate continuously, allowing year-round accessibility to quantized Hall resistance measurements. The nu = 2 plateau, with a value of R-K/2, also seen as RH, is used to scale to 1 k Omega using a binary cryogenic current comparator (BCCC) bridge and a direct current comparator (DCC) bridge. The uncertainties achieved with the BCCC are such as those obtained in the state-of-the-art measurements using GaAs-based devices. BCCC scaling methods can achieve large resistance ratios of 100 or more, and while room temperature DCC bridges have smaller ratios and lower current sensitivity, they can still provide alternate resistance scaling paths without the need for cryogens and superconducting electronics. Estimates of the relative uncertainties of the possible scaling methods are provided in this report, along with a discussion of the advantages of several scaling paths. The tabletop system limits are addressed as are potential solutions for using graphene standards at higher currents.