Near-Perfect Correlation of the Resistance Components of Mesoscopic Samples at the Quantum Hall Regime

We study the disorder dependence of the phase coherence time of quasi-one-dimensional wires and twodimensional ͑2D͒ Hall bars fabricated from a high mobility GaAs/AlGaAs heterostructure. Using an original ion implantation technique, we can tune the intrinsic disorder felt by the 2D electron gas and continuously vary the system from the semiballistic regime to the localized one. In the diffusive regime, the phase coherence time follows a power law as a function of diffusion coefficient as expected in the Fermi-liquid theory, without any sign of low-temperature saturation. Surprisingly, in the semiballistic regime, it becomes independent of the diffusion coefficient. In the strongly localized regime we find a diverging phase coherence time with decreasing temperature, however, with a smaller exponent compared to the weakly localized regime.

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“…[69][70][71][72][73][74][75][76][77] In such 2D systems, an estimation of the localization length loc 2D is given by 74,75 loc…”

Section: A 2d Hall Barsmentioning

confidence: 99%

Quantum coherence at low temperatures in mesoscopic systems: Effect of disorder

et al. 2010

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“…In this V sd region, electrons tunnel back and forth between the edge states and the localized puddles. Such tunneling effects have been studied extensively and are plausible [58][59][60] . When V sd becomes larger than V BD , the electrons in the bulk generate the avalanche and/or the QUILLS, and the QHE state breaks down.…”

Section: Possible Origins Of the Precursor Phenomenonmentioning

confidence: 99%

Observation of finite excess noise in the voltage-biased quantum Hall regime as a precursor for breakdown

et al. 2013

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We performed noise measurements in a two-dimensional electron gas to investigate the nonequilibrium quantum Hall effect (QHE) state. While excess noise is perfectly suppressed around the zero-biased QHE state reflecting the dissipationless electron transport of the QHE state, considerable finite excess noise is observed in the breakdown regime of the QHE. The noise temperature deduced from the excess noise is found to be of the same order as the energy gap between the highest occupied Landau level and the lowest empty one. Moreover, unexpected finite excess noise is observed at a finite source-drain bias voltage smaller than the onset voltage of the QHE breakdown, which indicates finite dissipation in the QHE state and may be related to the prebreakdown of the QHE.

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“…[2][3][4][5][6][7][8] In small samples the fluctuations take the form of sharp peaks, due to resonant scattering between opposite edges mediated by quasibound states in the bulk. 9 In larger samples the intermediate states form a percolating network at the plateau transition, resulting in a smooth peak in G bulk with rapid fluctuations superimposed.…”

Section: Introductionmentioning

confidence: 99%

Topological quantum number and critical exponent from conductance fluctuations at the quantum Hall plateau transition

et al. 2011

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The conductance of a two-dimensional electron gas at the transition from one quantum Hall plateau to the next has sample-specific fluctuations as a function of magnetic field and Fermi energy. Here we identify a universal feature of these mesoscopic fluctuations in a Corbino geometry: The amplitude of the magnetoconductance oscillations has an e 2 /h resonance in the transition region, signaling a change in the topological quantum number of the insulating bulk. This resonance provides a signed scaling variable for the critical exponent of the phase transition (distinct from existing positive definite scaling variables).

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Near-Perfect Correlation of the Resistance Components of Mesoscopic Samples at the Quantum Hall Regime

Cited by 20 publications

References 42 publications

Quantum coherence at low temperatures in mesoscopic systems: Effect of disorder

Quantum coherence at low temperatures in mesoscopic systems: Effect of disorder

Observation of finite excess noise in the voltage-biased quantum Hall regime as a precursor for breakdown

Topological quantum number and critical exponent from conductance fluctuations at the quantum Hall plateau transition

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