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

Chida, Kensaku; Arakawa, Tomoyuki; Matsuo, Sadashige; Nishihara, Yoko; Tanaka, Takahiro; Chiba, Daichi; Ono, Teruo; Hata, Tsujiaki; Kobayashi, Kensuke; Machida, Tomoki

doi:10.1103/physrevb.87.155313

Cited by 11 publications

(10 citation statements)

References 62 publications

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“…66 This requires the absence of backscattering, which is verified for our epitaxial graphene devices by the precision measurements of the quantized Hall resistance discussed before. This behavior was observed on GaAs/AlGaAs heterostructures quantum Hall devices 67,68,69 and is also verified for epitaxial graphene devices by our experiments. From the metrological point of view, this fact is an important prerequisite for low-noise precision measurements of the quantized Hall resistance.…”

Section: Magnetic Field Dependence Of 1/f Noisesupporting

confidence: 87%

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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Section: Magnetic Field Dependence Of 1/f Noisesupporting

confidence: 87%

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

et al. 2016

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“…We numerically fit the result of the current and the noise by using Eqs. (13) and (14). The window for the fitting was set such that |eV | < ∼ 3k B T , because we use FT for the expansion around A = eV /k B T = 0.…”

Section: B Experimentsmentioning

confidence: 99%

“…These few years, we are interested in noise in mesoscopic systems and have intensively performed the noise measurement in various systems, for example, quantum point contact [8][9][10][11][12], quantum wire [13], electron interferometer [14][15][16], quantum dot [17,18], magnetic tunnel junction [19][20][21][22][23], spin valve [24], and graphene [25,26]. In this Review, we discuss that the noise measurement can reveal the fundamental aspects of physical systems.…”

Section: Introductionmentioning

confidence: 99%

What can we learn from noise? — Mesoscopic nonequilibrium statistical physics —

Kobayashi

2016

Proceedings of the Japan Academy. Ser. B: Physical and Biologic

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Mesoscopic systems — small electric circuits working in quantum regime — offer us a unique experimental stage to explorer quantum transport in a tunable and precise way. The purpose of this Review is to show how they can contribute to statistical physics. We introduce the significance of fluctuation, or equivalently noise, as noise measurement enables us to address the fundamental aspects of a physical system. The significance of the fluctuation theorem (FT) in statistical physics is noted. We explain what information can be deduced from the current noise measurement in mesoscopic systems. As an important application of the noise measurement to statistical physics, we describe our experimental work on the current and current noise in an electron interferometer, which is the first experimental test of FT in quantum regime. Our attempt will shed new light in the research field of mesoscopic quantum statistical physics.

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“…Breakdown was extensively investigated in semiconductors [6,7,[11][12][13][14][15][16] and graphene [17][18][19][20], but mainly in Hall bars. Few experiments used constrictions [7,11], or Corbino geometries [21][22][23][24], with the purpose of achieving homogeneous current, or E-field, distributions.…”

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confidence: 99%

Landau Velocity for Collective Quantum Hall Breakdown in Bilayer Graphene

Yang

Graef

et al. 2018

Phys. Rev. Lett.

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1 Breakdown of the quantum Hall effect (QHE) is commonly associated with an electric field approaching the inter Landau-level (LL) Zener field, ratio of the Landau gap and cyclotron radius. Eluded in semiconducting heterostructures, in spite of extensive investigation, the intrinsic Zener limit is reported here using high-mobility bilayer graphene and high-frequency current noise. We show that collective excitations arising from electron-electron interactions are essential. Beyond a noiseless ballistic QHE regime a large superpoissonian shot noise signals the breakdown via inter-LL scattering. The breakdown is ultimately limited by collective excitations in a regime where phonon and impurity scattering are quenched. The breakdown mechanism can be described by a Landau critical velocity as it bears strong similarities with the roton mechanism of superfluids.The Fermi sea of a 2D electronic system is unstable at high magnetic field (B-field) toward the formation of discrete Landau levels, giving rise to the quantum Hall effect (QHE) [1], where the bulk is a Landau insulator. The QHE has led to many developments in physics, including recent ones in metrology [2,3] and quantum electronics [4]. The fate of the QHE at high electric field (E-field) remains an open question, as well as the nature of the phase reached when the drift velocity v d = E × B/B 2 approaches the cyclotron velocity R c ω c , where R c and ω c are the cyclotron radius and frequency, resulting in cyclotron orbit breaking. A precursor of the transition is the quantum Hall breakdown reported soon after the discovery of QHE [5-7]. The breakdown field E bd marks the onset of longitudinal resistance and dissipation. Its natural scale is the Zener field, E c ∼hω c /eR c , with ω c =eB/m * and R c ∼ √ Nl B , where m * is the effective mass, N the number of occupied LLs and l B = h/eB the magnetic length [8]. The relevance of the Zener mechanism was soon questioned as E c exceeds experimental E bd . Besides, genuine inter-LL tunneling suffers from a strong momentum mismatch at finite doping, ∆q = 2k F where k F = √ 2N/l B is the Fermi momentum [9]. It can be circumvented assuming impurity-assisted or phonon-mediated quasi-elastic inter LL scattering (QUILLS) [8,10]. Breakdown was extensively investigated in semiconductors [6,7,11-16] and graphene [17-20], but mainly in Hall bars. Few experiments used constrictions [7,11], or Corbino geometries [21-24], with the purpose of achieving homogeneous current, or E-field, distributions. In all cases breakdown E-fields are smaller than Zener fields, and critical Hall current densities J < ∼ 50 A/m [18]. The leading explanation thus shifted to a thermal instability, driven 2 by the imbalance between dissipation and phonon relaxation [25]; its threshold is materialdependent and lower than E c [17,18,26,27]. According to low-frequency noise measurements, the thermal instability eventually gives rise to electron avalanches [11,21,22]. On comparing breakdown (v bd = J bd /ne) and Zener (v c = E c /B) velocities one ...

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

Cited by 11 publications

References 62 publications

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

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

What can we learn from noise? — Mesoscopic nonequilibrium statistical physics —

Landau Velocity for Collective Quantum Hall Breakdown in Bilayer Graphene

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