Spatially resolved monitoring of the evolution of the breakdown of the quantum Hall effect: Direct observation of inter-Landau-level tunneling

Kaya, İsmet I.; Nachtwei, G.; Klitzing, K. von; Eberl, K.

doi:10.1209/epl/i1999-00563-6

Cited by 32 publications

(35 citation statements)

References 13 publications

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“…In the previous studies of Kaya et al, 6,7 the authors concluded that the relaxation and excitation of the electrons near the QHE breakdown are due to the inter-Landau-level transitions, which are triggered by Coulomb scattering at impurities. We can consider the case for the Hall bars and assume that these impurities are distributed homogeneously throughout the sample as shown in Fig.…”

Section: A a Simple Drift Modelmentioning

confidence: 98%

“…9 The reverse experiments of the excitation of electrons from the QH state to the dissipative state also showed a clear correlation between the mobility ͑or the scattering density͒ and the spatial evolution of the QHE breakdown along a constriction in the current path. 7,10 With increasing density of scatters ͑decreasing mobility͒, the avalanchelike breakdown became steeper along the drift direction. However, it was not possible to estimate the corresponding excitation times exc in these experiments.…”

Section: ͒mentioning

confidence: 99%

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Time scale of the excitation of electrons at the breakdown of the quantum Hall effect

et al. 2002

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We have investigated the time scale of the excitation of electrons leading to a transition from the quantum Hall ͑QH͒ state to the dissipative state in the two-dimensional electron systems of GaAs/AlGaAs heterostructures. The measurements were performed by applying nanosecond electric pulses to the current contacts of QH devices having various electron mobilities (1ϫ10 5 р H р9ϫ10 5 cm 2 /V s) at integer filling factors ϭ2, 4, and 6. The breakdown of the quantum Hall effect ͑QHE͒ occurs when the applied pulses exceed a critical pulse width t p c that is a function of pulse amplitude, magnetic field, and electron mobility (0.4рt p c р18 ns). By applying a simple drift model, we obtain an estimate for the critical drift lengths, which vary from about 1 to 25 m. No general differences of the response to short electric pulses have been found between Hall bar and Corbino devices. We interpret the critical times as drifting times between inelastic scattering events, and the critical lengths as related to the inelastic scattering lengths ᐉ in of electrons causing the QHE breakdown. Characteristic dependences of the critical drift times and lengths on the amplitude, filling factor, and the mobility have been observed and can be attributed to impurity-assisted inter-Landau-level tunneling.

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Section: A a Simple Drift Modelmentioning

confidence: 98%

Section: ͒mentioning

confidence: 99%

Time scale of the excitation of electrons at the breakdown of the quantum Hall effect

et al. 2002

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“…Longitudinal resistivity makes a rather gradual transition into dissipative regime with the increased current. Critical currents at filling factors ν = ±2 between the probes (6-7), (7)(8) at B = 11 T , T = 1.4 K. Inset shows ρ15,76 vs jx for ν = −2 with the full range of currents. b) σxx versus 1/jx in semilog scale.…”

Section: A)mentioning

confidence: 99%

“…b) σxx versus 1/jx in semilog scale. Inset shows fittings at filling factors ν = ±2 between the probes (6-7), (7)(8) at B = 11 T , T = 1.4 K for the region jx = 1 − 2 A/m. Fig.…”

Section: A)mentioning

confidence: 99%

Local breakdown of the quantum Hall effect in narrow single layer graphene Hall devices

Yanik

Kaya

2013

Solid State Communications

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We have analyzed the breakdown of the quantum Hall effect in 1 µm wide Hall devices fabricated from an exfoliated monolayer graphene transferred on SiOx. We have observed that the deviation of the Hall resistance from its quantized value is weakly dependent on the longitudinal resistivity up to current density of 5 A/m, where the Hall resistance remains quantized even when the longitudinal resistance increases monotonously with the current. Then a collapse in the quantized resistance occurs while longitudinal resistance keeps its gradual increase. The exponential increase of the conductivity with respect to the current suggests impurity mediated inter-Landau level scattering as the mechanism of the breakdown. The results are interpreted as the strong variation of the breakdown behavior throughout the sample due to the randomly distributed scattering centers that mediates the breakdown.

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“…Under quantizing conditions, high resistance contacts contribute to thermal excitation of electrons to higher Landau levels by Joule heating, leading to high uncertainty in metrological measurements of R K . 9 For GaAs heterostructures with alloyed AuGeNi contacts, it has been shown that high contact resistance values in the ∼kΩ range translate into deviations of the measured quantum Hall resistance from R K /2 up to 1 part per million. 10 Conversely, deviations can be <1 part per billion, if the resistance of the voltage contacts is below 100 Ω.…”

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confidence: 99%

Low contact resistance in epitaxial graphene devices for quantum metrology

et al. 2015

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We investigate Ti/Au contacts to monolayer epitaxial graphene on SiC (0001) for applications in quantum resistance metrology. Using three-terminal measurements in the quantum Hall regime we observed variations in contact resistances ranging from a minimal value of 0.6 Omega up to 11 k Omega. We identify a major source of high-resistance contacts to be due bilayer graphene interruptions to the quantum Hall current, whilst discarding the effects of interface cleanliness and contact geometry for our fabricated devices. Moreover, we experimentally demonstrate methods to improve the reproducibility of low resistance contacts (less than 10 Omega) suitable for high precision quantum resistance metrology.

Funding Agencies|Graphene Flagship [CNECT-ICT-604391]; Swedish Foundation for Strategic Research (SSF); Linnaeus Centre for Quantum Engineering; Knut and Alice Wallenberg Foundation; Chalmers AoA Nano; Swedish-Korean Basic Research Cooperative Program of the NRF [2014R1A2A1A1 2067266]; EMRP project GraphOhm; EMRP within EURAMET; EMRP within European Union

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Spatially resolved monitoring of the evolution of the breakdown of the quantum Hall effect: Direct observation of inter-Landau-level tunneling

Cited by 32 publications

References 13 publications

Time scale of the excitation of electrons at the breakdown of the quantum Hall effect

Time scale of the excitation of electrons at the breakdown of the quantum Hall effect

Local breakdown of the quantum Hall effect in narrow single layer graphene Hall devices

Low contact resistance in epitaxial graphene devices for quantum metrology

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