Series connection of quantum Hall resistance array and programmable Josephson voltage standard for current generation at one microampere

Abstract

An accurate current would be realized by a series connection of an invariant voltage and resistance with zero interconnection resistance in the framework of Ohm’s law. In practice, however, accurate current realization is limited by the temporal drift and instability of employed resistors, solid-state voltage sources and interconnection wires against environmental fluctuations, such as temperature or atmospheric pressure. Here, we generated a current of 1 μA, determined by the Josephson voltage and quantized Hall resistance array. A programmable Josephson voltage standard (PJVS), 1 MΩ quantized Hall resistance array (QHRA) and ultrastable low noise current amplifier (ULCA) are connected in series to generate and measure a current of 1 μA. The expected current is calculated as the ratio of the Josephson voltage to the QHRA plus the output resistance of the PJVS. The relative difference between the current measured by the ULCA and the calculated current is as small as 40 nA/A with a combined measurement uncertainty (k=1) of 0.13 μA/A.

Optimization of graphene-based quantum Hall arrays for recursive star–mesh transformations

“…This common single-value constraint severely limits the infrastructure and equipment with which one may disseminate the unit of the ohm. Two dominant approaches to remove these limitations include: (1) quantum Hall array resistance standards (QHARS) to link multiple Hall elements in parallel or series, and (2) the use of p-n junctions, with both approaches yielding resistances of 𝑞𝑅 where q is a positive rational number [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Generally, standardization of electrical quantities has a broad importance to physics, including measurements of electrical properties like resistivity and Hall effect, and enable precise understanding of a material's electronic structure and behavior [18][19][20][21].…”