Revised technical guidelines for reliable dc measurements of the quantized Hall resistance

Delahaye, F.; Jeckelmann, B.

doi:10.1088/0026-1394/40/5/302

Cited by 156 publications

(163 citation statements)

References 26 publications

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“…In figure 4d, the Landau level bending is sketched under thermal equilibrium; in figure 4e, under small Hall voltage bias V H . 2 Because of this bias, the electrostatic potential drop over the innermost incompressible strip on the left-hand edge is enhanced by a V H (a ≈ 0.5); therefore, the dissipation-less current flowing along this incompressible strip is increased by DI x = i e 2 /h · a V H . On the right-hand edge, the drop is diminished by (1 − a) V H and therefore the current, flowing in the opposite direction to the left edge, is decreased by about DI x = i e 2 /h · (1 − a) V H .…”

Section: Current Distribution and Quantized Hall Resistancementioning

confidence: 99%

Metrology and microscopic picture of the integer quantum Hall effect

Weis

Klitzing

2011

Phil. Trans. R. Soc. A.

103

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Since 1990, the integer quantum Hall effect has provided the electrical resistance standard, and there has been a firm belief that the measured quantum Hall resistances are described only by fundamental physical constants-the elementary charge e and the Planck constant h. The metrological application seems not to rely on detailed knowledge of the microscopic picture of the quantum Hall effect; however, technical guidelines are recommended to confirm the quality of the sample to confirm the exactness of the measured resistance value. In this paper, we give our present understanding of the microscopic picture, derived from systematic scanning force microscopy investigations on GaAs/(AlGa)As quantum Hall samples, and relate these to the technical guidelines.

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Section: Current Distribution and Quantized Hall Resistancementioning

confidence: 99%

Metrology and microscopic picture of the integer quantum Hall effect

Weis

Klitzing

2011

Phil. Trans. R. Soc. A.

103

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“…The main limitation in the CCC measurements appeared to be the contact resistance of the voltage contacts [13]. The rather high resistances induce additional measurement noise and fluctuations in the voltage contacts thereby limiting the attainable accuracy of quantum-Hall precision experiments.…”

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confidence: 99%

Quantum resistance metrology in graphene

Giesbers

Rietveld

Houtzager

et al. 2008

Applied Physics Letters

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We have performed a metrological characterization of the quantum Hall resistance in a 1 µm wide graphene Hall-bar. The longitudinal resistivity in the center of the ν = ±2 quantum Hall plateaus vanishes within the measurement noise of 20 mΩ upto 2 µA. Our results show that the quantization of these plateaus is within the experimental uncertainty (15 ppm for 1.5 µA current) equal to that in conventional semiconductors. The principal limitation of the present experiments are the relatively high contact resistances in the quantum Hall regime, leading to a significantly increased noise across the voltage contacts and a heating of the sample when a high current is applied. The Hall resistance in two-dimensional electron systems (2DESs) is quantized in terms of natural constants only, R H = h/ie 2 with i an integer number [1]. Due to its high accuracy and reproducibility this quantized Hall resistance in conventional 2DESs is nowadays used as a universal resistance standard [2].Recently a new type of half-integer quantum Hall effect [3,4] was found in graphene, the purely twodimensional form of carbon [5]. Its unique electronic properties [6] (mimicking the behavior of charged chiral Dirac fermions [7,8]) allow the observation of a quantized Hall resistance up to room-temperature [9, 10], making graphene a promising candidate for a high-temperature quantum resistance standard. Although the quantized resistance in graphene around the ν = 2 plateau is generally believed to be equal to h/2e 2 , up to now it has not been shown to meet a metrological standard. In this Letter we present results of the first metrological characterization of the quantum Hall resistance in graphene. In particular, we will address the present accuracy of quantization (15 ppm) and the experimental conditions limiting this accuracy.Our sample consists of a graphene Hall-bar on a Si/SiO 2 substrate forming a charge-tunable ambipolar field-effect transistor (A-FET), where the carrier concentration can be tuned with a back-gate voltage V g [11]. In order to remove most of the surface dopants that make graphene generally strongly hole doped and limit its mobility, we have annealed the sample in-situ for several hours at 380 K prior to cooling it down slowly (∆T /∆t < 3 K/min) to the base temperature (0.35 K) of a toploading 3 He-system equipped with a 15 T superconducting magnet. After annealing, the charge neutrality point in the A-FET was situated at 5 V and the sample dis- * Electronic address: J.Giesbers@science.ru.nl † Electronic address: U.Zeitler@science.ru.nl 2 µm

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“…Under some experimental conditions and following specific technical guidelines [51], the independence of R K on QHE device characteristics (type, materials, channel width, contacts), the number i and experimental parameters (temperature, measuring current, magnetic field) has been demonstrated at levels down to a few parts in 10 10 [52,53]. Moreover, on-site bilateral comparisons of complete QHE systems carried out between the Bureau International des Poids et Mesures (BIPM) and some NMIs during the past decades [54][55][56][57][58] or more recent comparisons via 1 X or 100 X travelling standards have shown excellent agreement of a few parts in 10 9 [59,60].…”

Section: Introductorymentioning

confidence: 99%