Quantum Hall resistance standard in graphene devices under relaxed experimental conditions

Ribeiro-Palau, Rebeca; Lafont, F.; Brun-Picard, J.; Kazazis, Dimitrios; Michon, A.; Cheynis, Fabien; Couturaud, O.; Conséjo, Christophe; Jouault, Benoît; Poirier, W.; Schopfer, F.

doi:10.1038/nnano.2015.192

Cited by 174 publications

(142 citation statements)

References 42 publications

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“…To the data in Figure 2 we fitted a power law of the form + ( /nA) which had successfully been used in extrapolating the Hall resistance of a GaAs-based QHE device in the fractional QH state at filling factor 1/3 recently [19] and which also has been observed for an integer QHE device [23]. Interestingly, in all cases an exponent of 3 is observed in this power law, for the cited IQHE and FQHE measurements as well as for the QAHE result obtained here.…”

Section: In This Tablementioning

confidence: 99%

Precision measurement of the quantized anomalous Hall resistance at zero magnetic field

Götz

Fijalkowski

Pesel

et al. 2018

Applied Physics Letters

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In the quantum anomalous Hall effect, the edge states of a ferromagnetically doped topological insulator exhibit quantized Hall resistance and dissipationless transport at zero magnetic field. Up to now, however, the resistance was experimentally assessed with standard transport measurement techniques which are difficult to trace to the von-Klitzing constant RK with high precision. Here, we present a metrologically comprehensive measurement, including a full uncertainty budget, of the resistance quantization of V-doped (Bi,Sb)2Te3 devices without external magnetic field. We established as a new upper limit for a potential deviation of the quantized anomalous Hall resistance from RK a value of 0.26 ± 0.22 ppm, the smallest and most precise value reported to date. This provides another major step towards realization of the zero-field quantum resistance standard which in combination with Josephson effect will provide the universal quantum units standard in the future.Quantum standards are the backbone of the system of measurement units. Already since 1990 all electrical units are based on flux quantization in units of ℎ 2 ⁄ , realized with the Josephson effect [1,2], and conductance quantization in units of 2 ℎ ⁄ , realized with the quantized Hall effect (QHE) [3,4]. With the revision of the international system of units, SI, in near future [5,6] also the realizations of the units of mass [7,8], the kilogram, and of temperature [9,10], the Kelvin, will utilize and rely on practical electric quantum standards, realizing the vision of Maxwell [11] and Planck [12] of a truly universal system of units. Both electrical quantum standards require temperatures of 4 K or lower for their operation, but since in addition the QHE only works in a magnetic field, it is practically impossible to combine both in one system. However, in ferromagnetic topological insulators like e.g. Cr-or V-doped (Bi,Sb)2Te3, the quantum anomalous Hall effect (QAHE) provides conductance quantization without a magnetic field [13][14][15][16], giving legitimate hope for a future quantum standard where all units based on ℎ and can be realized in one measurement setup.Yet, up to now the precision of the QAHE has not been tested with precision metrology methods, and in particular no uncertainty budgets were presented with the data published [17,18]. Indeed, the fact that very low measurement currents are required makes it difficult to reach uncertainties in the parts in 10 9 range as are routinely obtained in calibrations based on GaAs or graphene QHE devices. A main reason for the limitation of current is the robustness of the ferromagnetic state, which at this stage of development still requires temperatures in the mK-regime and does not tolerate current levels

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Section: In This Tablementioning

confidence: 99%

Precision measurement of the quantized anomalous Hall resistance at zero magnetic field

Götz

Fijalkowski

Pesel

et al. 2018

Applied Physics Letters

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“…The quantum plateaus in G/SiC devices are much larger in magnetic field than those obtained in graphene encapsulated in hBN [7], because they are stabilized by charge transfer [8] and disorder [9]. Thanks to these properties, it was recently demonstrated that G/SiC can act as a quantum electrical resistance standard [10], even in experimental conditions relaxed with respect to the state of the art in GaAs-based quantum wells [11].…”

Section: Introductionmentioning

confidence: 99%

Magnetic field driven ambipolar quantum Hall effect in epitaxial graphene close to the charge neutrality point

et al. 2017

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We have investigated the disorder of epitaxial graphene close to the charge neutrality point (CNP) by various methods: (i) at room temperature, by analyzing the dependence of the resistivity on the Hall coefficient; (ii) by fitting the temperature dependence of the Hall coefficient down to liquid helium temperature; (iii) by fitting the magnetoresistances at low temperature. All methods converge to give a disorder amplitude of (20 ± 10) meV. Because of this relatively low disorder, close to the CNP, at low temperature, the sample resistivity does not exhibit the standard value h/4e 2 but diverges. Moreover, the magnetoresistance curves have a unique ambipolar behavior, which has been systematically observed for all studied samples. This is a signature of both asymmetry in the density of states and in-plane charge transfer. The microscopic origin of this behavior cannot be unambiguously determined. However, we propose a model in which the SiC substrate steps qualitatively explain the ambipolar behavior.

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“…Low-frequency noise, also referred to as flicker noise or 1/f noise, is a common phenomenon caused by various physical mechanisms and found in numerous systems [4,5], including electronic transport in graphene devices [6][7][8][9]. At low temperature, the noise properties of graphene are of particular interest for its application in metrology as a quantum Hall resistance [10][11][12][13] and impedance [14] standard. In low-temperature diffusive transport in a disordered conductor like graphene, quantum interference effects arise due to the phase-coherent transport of electrons.…”

Section: Introductionmentioning

confidence: 99%

Nonequilibrium mesoscopic conductance fluctuations as the origin of 1/f noise in epitaxial graphene

et al. 2016

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We investigate the 1/f noise properties of epitaxial graphene devices at low temperatures as a function of temperature, current, and magnetic flux density. At low currents, an exponential decay of the 1/f noise power spectral density with increasing temperature is observed that indicates mesoscopic conductance fluctuations as the origin of 1/f noise at temperatures below 50 K. At higher currents, deviations from the typical quadratic current dependence and the exponential temperature dependence occur as a result of nonequilibrium conditions due to current heating. By applying the Kubakaddi theory [S. S. Kubakaddi, Phys. Rev. B 79, 075417 (2009)], a model describing the 1/f noise power spectral density of nonequilibrium mesoscopic conductance fluctuations in epitaxial graphene is developed and used to determine the energy loss rate per carrier. In the regime of Shubnikov-de Haas oscillations, a strong increase of 1/f noise is observed, which we attribute to an additional conductance fluctuation mechanism due to localized states in quantizing magnetic fields. When the device enters the regime of quantized Hall resistance, the 1/f noise vanishes. It reappears if the current is increased and quantum Hall breakdown sets in.

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Quantum Hall resistance standard in graphene devices under relaxed experimental conditions

Cited by 174 publications

References 42 publications

Precision measurement of the quantized anomalous Hall resistance at zero magnetic field

Precision measurement of the quantized anomalous Hall resistance at zero magnetic field

Magnetic field driven ambipolar quantum Hall effect in epitaxial graphene close to the charge neutrality point

Nonequilibrium mesoscopic conductance fluctuations as the origin of 1/f noise in epitaxial graphene

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