| Autor: |
Rigosi AF; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA., Panna AR; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA., Payagala SU; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA., Kruskopf M; Joint Quantum Institute, University of Maryland, College Park, MD 20742 USA., Kraft ME; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA., Jones GR; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA., Wu BY; Graduate Institute of Applied Physics, National Taiwan University, Taipei 10617, Taiwan., Lee HY; Theiss Research, La Jolla, CA 92037 USA., Yang Y; Joint Quantum Institute, University of Maryland, College Park, MD 20742 USA., Hu J; Joint Quantum Institute, University of Maryland, College Park, MD 20742 USA., Jarrett DG; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA., Newell DB; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA., Elmquist RE; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA. |
| Abstrakt: |
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 ν = 2 plateau, with a value of R K /2, also seen as R H , is used to scale to 1 kΩ 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. |
