Universal conductance fluctuations in silicon inversion-layer nanostructures

Skocpol, WJ; Pm, Mankiewich; Howard, R. E.; Jackel, LD; Tennant, D. M.; Ad, Stone

doi:10.1103/physrevlett.56.2865

Cited by 253 publications

(55 citation statements)

References 22 publications

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“…Most notably in that the fluctuation pattern produced is like a set of 'finger-prints' characteristic of a particular structural, frozen-in configuration. However, the underlying mechanisms for the two phenomena are different; The UCF is a quantum interference effect usually produced by sweeping a magnetic field H that modulates G via the Aharonov-Bohm effect (similar behavior has been observed in gate experiments on diffusive samples, likewise related to an interference effect [13]). The CF observed here is associ-ated with a mechanism offered by Lee [14] to account for experiments on quasi-one dimensional hopping samples [15].…”

Section: Conductance Fluctuationsmentioning

confidence: 90%

Electron glass in samples approaching the mesoscopic regime

Orlyanchik

Ovadyahu

2007

Phys. Rev. B

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We study the dependence of the glassy properties of strongly localized In2O3−x films on the sample lateral dimensions. Characteristic mesoscopic effects such as reproducible conductance fluctuations (CF) are readily observable in gated structures for sample size smaller than 100 µm measured at 4 K, and the relative amplitude of the CF decreases with the sample volume as does the flicker noise. By contrast, down to sample size of few microns, the non-equilibrium features that are attributed to the electron-glass are indistinguishable from those observed in macroscopic samples, and in particular, the relaxation dynamics is independent of sample size down to 2 µm. In addition, The usual features that characterize the electron-glass including slow-relaxation, memory effects, and full-aging behavior are all observed in the 'mesoscopic' regime, and they appear to be independent of the conductance fluctuations.

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Section: Conductance Fluctuationsmentioning

confidence: 90%

Electron glass in samples approaching the mesoscopic regime

Orlyanchik

Ovadyahu

2007

Phys. Rev. B

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“…4 However, it is difficult to sort out the contribution of quantum corrections to the magnetoresistance from other possible mechanisms such as two types of charge carriers and inhomogeneities.There is therefore a need for a different type of measurement sensitive solely to the mesoscopic phase coherence, such as universal conductance fluctuations (UCF). [5][6][7] It has been shown that the conductivity of sample with a given impurity concentration will fluctuate around it's average value upon changing the impurity configuration. For two dimensions these fluctuations should have a universal value of the order of e 2 h .…”

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confidence: 99%

Phase coherent transport inSrTiO3/LaAlO3interfaces

et al. 2010

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The two dimensional electron gas formed between the two band insulators SrTiO3 and LaAlO3 exhibits a variety of interesting physical properties which make it an appealing material for use in future spintronics and/or quantum computing devices. For this kind of applications electrons have to retain their phase memory for sufficiently long times or length. Using a mesoscopic size device we were able to extract the phase coherence length, L φ and its temperature variation. We find the dephasing rate to have a power law dependence on temperature. The power depends on the temperature range studied and sheet resistance as expected from dephasing due to strong electron-electron interactions.

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“…The resistance as a function of gate voltage V G in Figure 1a shows the usual maximum in resistance (at the NP) with charge carrier density increasing for V G on either side of the maximum. The strong irregular fluctuations that decorate R(V G ) at low temperature are an example of universal conduction fluctuations [12][13][14][15][16][17][18] which are observed in, for example, Si inversion layers, typically below helium temperatures 14,15 . In our case, these mesoscopic resistance fluctuations (MRFs) originate from the interference of electrons scattered from a particular distribution of scattering centres as the charge carrier density is changed by varying V G .…”

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Correlation between resistance fluctuations and temperature dependence of conductivity in graphene

et al. 2009

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The weak temperature dependence of the resistance R(T) of monolayer graphene 1-3 indicates an extraordinarily high intrinsic mobility of the charge carriers. Important complications are the presence of mobile scattering centres that strongly modify charge transport, and the presence of strong mesoscopic conductance fluctuations that, in graphene, persist to relatively high temperatures 4,5 . In this Letter, we investigate the surprisingly varied changes in resistance that we find in graphene flakes as temperature is lowered below 70 K. We propose that these changes in R(T) arise from the temperature dependence of the scattered electron wave interference that causes the resistance fluctuations. Using the field effect transistor configuration, we verify this explanation in detail from measurements of R(T) by tuning to different gate voltages corresponding to particular features of the resistance fluctuations. We propose simple expressions that model R(T) at both low and high charge carrier densities.Recently, several papers have presented systematic analyses of R(T) data in graphene [1][2][3] . Morozov et al.1 ascribed the strong increase of resistivity above a temperature of 200 K to scattering by flexural phonons 6 localized in ripples in the graphene sheet. Chen et al. 2 fitted their R(T) data to the usual linear term due to scattering by acoustic phonons and Bose-Einstein functions for scattering from specific high-energy phonons. They concluded that scattering by a pair of interfacial phonons in the SiO 2 substrate 7 was the most likely origin of the increase of R(T) at high temperatures, but also noted that their resistivity increase at high T was consistent with scattering by phonons of energy 104 meV. To eliminate the role of the substrate in limiting conductivity, Bolotin et al.3 investigated a suspended graphene flake, achieving near-ballistic transport with mobility ~120,000 cm 2 /Vs at 240 K. The resistivity increased linearly from 50 K to 240 K suggesting that longitudinal acoustic phonons were the main scatterers.For low charge carrier densities near the charge neutrality point (NP), the resistivity is less well understood, generally increasing as temperature decreases but sometimes showing a decrease below 150 K 1,8 . Cho and Fuhrer 9 and Chen et al. 10 concluded that the resistance of their graphene samples near the neutrality point (NP) was governed not by the physics of the Dirac singularity but by carrier-density inhomogeneities induced by the potential of charged impurities ("puddles" of electrons and holes as imaged by Martin et al. 11 ).We have measured the resistance of monolayer graphene samples as a function of temperature and gate voltage (see Methods section for details). Figure 1 shows a typical resistance at T = 4.2 K of a portion of graphene of length 1200 nm and width 1450 nm. The resistance as a function of gate voltage V G in Figure 1a shows the usual maximum in resistance (at the NP) with charge carrier density increasing for V G on either side of the maximum. The strong irregul...

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Universal conductance fluctuations in silicon inversion-layer nanostructures

Cited by 253 publications

References 22 publications

Electron glass in samples approaching the mesoscopic regime

Electron glass in samples approaching the mesoscopic regime

Phase coherent transport inSrTiO3/LaAlO3interfaces

Correlation between resistance fluctuations and temperature dependence of conductivity in graphene

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