High-precision measurements of the quantized Hall resistance:Experimental conditions for universality

Jeckelmann, B.; Jeanneret, B.; Inglis, D.

doi:10.1103/physrevb.55.13124

Cited by 75 publications

(73 citation statements)

References 26 publications

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“…At short distances and in the linear low current regime, such a nonequilibrium situation leads to the observation of the reported nonlocal resistances. 32,33 In this context, it is well established that high contact quality is crucial for the observability of the exact quantization 34,35 as well as for correct determination of the longitudinal resistivity in Hall bars. Our samples are also rather large (bar width and contact distances typically 1 mm) in order to omit narrow channel effects or poor equilibration between the probes.…”

Section: Sample Properties and Measurement Techniquementioning

confidence: 99%

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Electronic transport and the localization length in the quantum Hall effect

Furlan

1998

Phys. Rev. B

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We report on recent experimental results from transport measurements with large Hall bars made of high mobility GaAs/AlGaAs heterostructures. Thermally activated conductivities and hopping transport were investigated in the integer quantum Hall regime. The predominant transport processes in two dimensions are discussed. The implications of transport regime on prefactor universality and on the relation between ρxx and ρxy are studied. Particularly in the Landau level tails, strictly linear dependence δρxy(ρxx) was found, with pronounced asymmetries with respect to the plateau centre. At low temperatures, Ohmic (temperature dependent) as well as non-Ohmic (current dependent) transport were investigated and analysed on the basis of variable-range hopping theory. The non-Ohmic regime could successfully be described by an effective electron temperature model. The results from either the Ohmic transport or from a comparison of Ohmic and non-Ohmic data allowed to determine the localization length ξ in two different ways. The observed divergence of ξ(ν) with the filling factor ν approaching a Landau level centre, is in qualitative agreement with scaling theories of electron localization. The absolute values of ξ far from the ρxx peaks are compared with theoretical predictions. On one hand, discrepancies between the ξ results obtained from the two experimental methods are attributed to an inhomogeneous electric field distribution. Extrapolation yields an effective width of dominant potential drop of about 100 µm. On the other hand, our analysis suggests a divergence of the dielectric function ǫr ∝ ξ β with β ≃ 1.

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Section: Sample Properties and Measurement Techniquementioning

confidence: 99%

“…Further details on the samples may also be found in Ref. 34. Each Hall bar had three equidistant voltage probes on each side, which, upon injection of a dc current J, were all measured simultaneously, yielding the potential drop V ij across any contact pair combination.…”

Section: Sample Properties and Measurement Techniquementioning

confidence: 99%

Electronic transport and the localization length in the quantum Hall effect

Furlan

1998

Phys. Rev. B

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“…Whenever the Fermi energy lies inside a mobility gap between two Landau levels 3 , transversal resistivity becomes equal to R K /ν, where the filling factor ν is an integer, and longitudinal resistivity vanishes. It has been established that as long as good quantization 4 is achieved, the value of quantum Hall resistance is universal, that is, does not depend on the device nor the material within the best available measurement precision [5][6][7] . The ultimate precision, which in the most accurate experiments is on the order of 10 −10 , is typically set by the signal to noise ratio which, in turn, is limited by the QHE breakdown.…”

Section: Introductionmentioning

confidence: 99%

A prototype of RK/200 quantum Hall array resistance standard on epitaxial graphene

Lartsev

Lara‐Avila

Danilov

et al. 2015

Journal of Applied Physics

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Epitaxial graphene on silicon carbide is a promising material for the next generation of quantum Hall resistance standards. Single Hall bars made of graphene have already surpassed their state-of-the-art GaAs based counterparts as an R K /2 (R K = h/e 2 ) standard, showing at least the same precision and higher breakdown current density. Compared to single devices, quantum Hall arrays using parallel or series connection of multiple Hall bars can offer resistance values spanning several orders of magnitude and (in case of parallel connection) significantly larger measurement currents, but impose strict requirements on uniformity of the material. To evaluate the quality of the available material, we have fabricated arrays of 100 Hall bars connected in parallel on epitaxial graphene. One out of four devices has shown quantized resistance that matched the correct value of R K /200 within the measurement precision of 10 −4 at magnetic fields between 7 and 9 Tesla. The defective behaviour of other arrays is attributed mainly to non-uniform doping. This result confirms the acceptable quality of epitaxial graphene, pointing towards the feasibility of well above 90% yield of working Hall bars.

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“…One interesting question has been raised that if graphene can replace GaAs to be the base of the resistance standard [16,17]. The QH effect has been applied on the resistance unit in the 2 international system since 1990 [18].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear transport of graphene in the quantum Hall regime

et al. 2016

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We have studied the breakdown of the integer quantum Hall (QH) effect with fully broken symmetry, in an ultra-high mobility graphene device sandwiched between two single crystal hexagonal boron nitride substrates. The evolution and stabilities of the QH states are studied quantitatively through the nonlinear transport with dc Hall voltage bias. The mechanism of the QH breakdown in graphene and the movement of the Fermi energy with the electrical Hall field are discussed. This is the first study in which the stabilities of fully symmetry broken QH states are probed all together. Our results raise the possibility that the = ±6 states might be a better target for the quantum resistance standard. IntroductionGraphene, a single layer of graphite, has continued to attract great attention from the scientific and technical communities due to the rich physics of Dirac fermions and the great potential for technological applications [1]. Started from the half-integer and the four fold degeneracy without symmetry breaking of spin or valley degrees of freedom, the quantum Hall (QH) resistance in graphene is expected to be the series of filling factor = ±2, ±6, ±10……., and those Hall plateaus have been experimentally observed since 2005 [2,3]. With the technique of suspending graphene [4] and transferring graphene onto single crystal hexagonal boron nitride (hBN) [5], one can suppress the scattering of carriers from charged impurities [6] and substrate phonons [7], resulting in substantially improved carrier mobility. Symmetry-broken integer QH states and fractional QH states were soon discovered on the improved devices [8][9][10][11][12][13][14][15].Although most of the integer QH and fractional QH studies have been carried in GaAs/AlGaAs heterostructure for its extremely high mobility, similar studies in graphene have attracted lots of attention for a variety of reasons including the peculiar band structure of graphene and the exposure of the two dimensional electron gas (2DEG) in graphene. One interesting question has been raised that if graphene can replace GaAs to be the base of the resistance standard [16,17]. The QH effect has been applied on the resistance unit in the 2 international system since 1990 [18]. However, a redefinition of SI basic units (Kilogram, Ampere, Kelvin and Mole) by 2018 [19] involves the resistance standard from the QH effect. Therefore, the metrology of resistance standard, including a practical (non-SI) definition for increasing potential end users, is getting more and more important. Various works have proved the universality and reproducibility of quantum Hall resistance standard metrology in graphene with accuracy as high as part-per-billion [20][21][22][23][24]. Quantum resistance devices based on graphene have been realized on graphene grown on silicon carbide wafer [20][21][22][23][24][25][26]. More importantly, QH effect can be realized in graphene at room temperature [27], which makes graphene-based QH device a very attractive choice of a practical resistance definition for routine...

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High-precision measurements of the quantized Hall resistance:Experimental conditions for universality

Cited by 75 publications

References 26 publications

Electronic transport and the localization length in the quantum Hall effect

Electronic transport and the localization length in the quantum Hall effect

A prototype of RK/200 quantum Hall array resistance standard on epitaxial graphene

Nonlinear transport of graphene in the quantum Hall regime

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