The experiments described in this article were carried out with the primary goal of exploring the temperature dependence of the quantum Hall resistance on a standards-quality device.
Pepper, New Method for High-Accuracy Determination of the Fine-Structure Constant Based on Quantized Hall Resistance, Phys.
An important step in developing the ac quantized Hall resistance (ac QHR) [1-10] as an intrinsic impedance standard based on the dc QHR [11-13] is to measure the dc QHR guideline properties  and the dc and ac QHR values without changing sample probe lead contacts at the QHR device.
We demonstrate that dc quantized Hall resistance (dc QHR) guideline properties and dc and ac QHR values can be measured without changing sample probe lead connections at the QHR device, and report ac QHR values that converge to the dc QHR value when using four-terminal-pair ac QHR measurements.
A similarly universal quantity known as the quantized Hall resistance
has more recently become available as a standard for the ohm, the unit of electrical resistance.
By producing samples of sufficient size and quality, and accurately demonstrate Hall resistance
, the team proved that graphene has the potential to supersede conventional semiconductors on a mass scale.
von Klitzing's discovery of the Quantum Hall Effect and listed on The National Institute of Standards and Technology Reference on Constants, Units and Uncertainty, describes a phenomenon exhibited by certain semiconductor devices at low temperatures and high magnetic fields, whereby the Hall resistance becomes precisely equal to (h/e(2))/n, where h is Planck's constant, e is the electronic charge, and n is either an integer or a rational fraction.
The ratio of this voltage to the current is called the Hall Resistance.
Jeanneret, Material, device, and step independence of the quantized Hall resistance
, IEEE Trans.
This current is measured as a voltage drop that is generated as it passes through a resistance calibrated against the quantum Hall resistance
It will serve as a "turnkey" primary representation for capacitance, provide an additional route for the measurement of the fine-structure constant and provide a means to close the "quantum metrology triangle" formed by the Josephson voltage, the quantum Hall resistance
, and the fundamental electron charge.
A NIST scientist has developed a new technique that enables more accurate scaling from the primary NIST quantum Hall resistance
standard to high resistance levels of 1 M[ohm] and above.