Non-Gaussian effects in 1/<i>f</i>noise in small silicon-on-sapphire resistors

Restle, P.J.; Hamilton, R.J.; Weissman, M. B.; Love, M. S.

doi:10.1103/physrevb.31.2254

Cited by 64 publications

(40 citation statements)

References 8 publications

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“…The second spectrum is a sensitive technique to estimate the presence of non-Gaussian component (NGC) in the resistance fluctuations [15,31,32]. The experimental scheme employed to measure the second spectrum is shown in Fig.…”

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confidence: 99%

Correlated Conductance Fluctuations Close to the Berezinskii-Kosterlitz-Thouless Transition in Ultrathin NbN Films

et al. 2013

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We probe the presence of long-range correlations in phase fluctuations by analyzing the higherorder spectrum of resistance fluctuations in ultra-thin NbN superconducting films. The nonGaussian component of resistance fluctuations is found to be sensitive to film thickness close to the transition, which allows us to distinguish between mean field and Berezinskii-Kosterlitz-Thouless (BKT) type superconducting transitions. The extent of non-Gaussianity was found to be bounded by the BKT and mean field transition temperatures and depend strongly on the roughness and structural inhomogeneity of the superconducting films. Our experiment outlines a novel fluctuation-based kinetic probe in detecting the nature of superconductivity in disordered low-dimensional materials.The transition from superconducting to normal state in two-dimensions is known to occur via BerezinskiiKosterlitz-Thouless (BKT) mechanism. Traditionally, the signature of BKT transition is found by measuring the superfluid density where a discontinuity is observed at the critical temperature T BKT [1][2][3]. This method is limited in its scope of application for systems exhibiting interfacial/buried superconductivity like oxide heterostructures due to the inability to measure the thickness of the superconducting layer accurately. Transport-based probes including discontinuity in the power law behavior of I-V characteristics or change in the curvature of magnetoresistance from convex to concave in the presence of a perpendicular magnetic field [4][5][6][7][8][9] have their limitations as real systems contain some degree of inhomogeneity which smear out the signatures of BKT type behavior. With growing interest in lowdimensional superconductivity, it is interesting to develop new probes/techniques that are not only sensitive enough to detect BKT transition but also compare its characteristics scales with the mean field description.The BKT transition, as exhibited by ultra-thin superconducting films, is characterized by the unbinding of vortex pairs beyond T BKT . It is well known that these vortices exhibit long-range interactions which vary logarithmically with the distance between the vortices. Vortices also occur in bulk Type-II superconductors in the presence of an external magnetic field. Earlier experiments probing vortices in bulk films through measurements of flux flow noise and voltage noise have reported the presence of broad band noise (BBN) [10,11] as a function of driving current and magnetic field. The statistics of noise in these systems is non-Gaussian due to the fact that most of the noise arise from very few fluctuators. Noise measurements on quasi-2D MgB 2 films show a possibility of thermally induced vortex hopping through measurements of flux noise close to BKT transition [12]. To the best of our knowledge there are no reports on higher-order statistics of fluctuations looking into the possibility of interacting vortices in two-dimensions.Higher-order fluctuations in resistivity has been established as an useful tool to study the pres...

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confidence: 99%

Correlated Conductance Fluctuations Close to the Berezinskii-Kosterlitz-Thouless Transition in Ultrathin NbN Films

et al. 2013

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“…Experiments are inconclusive whether these systems self organize to the critical state over a broad range of external field [5,6,7,8,9], or if there exists a unique critical point that is smudged by a wide critical zone as postulated by the concept of "plain-old criticality" [4,10,11]. The bottleneck arises since most experimental claims of critical behavior are based on observation of a scale-free kinetics which causes power law decay in size distribution or the power spectrum of the avalanches [6,9], but none of these are direct probes to ξ itself.In systems with many degrees of freedom [12,13], the non-gaussian component (NGC) in time dependent fluctuations (or noise) in physical observables act as an indicator of long-range correlation between individual fluctuators [14,15]. This has been studied in the context of Barkhausen noise from magnetization avalanches, which probes the role of long-range magnetic interactions in the domain wall depinning when subjected to external magnetic field [16].…”

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confidence: 99%

“…In systems with many degrees of freedom [12,13], the non-gaussian component (NGC) in time dependent fluctuations (or noise) in physical observables act as an indicator of long-range correlation between individual fluctuators [14,15]. This has been studied in the context of Barkhausen noise from magnetization avalanches, which probes the role of long-range magnetic interactions in the domain wall depinning when subjected to external magnetic field [16].…”

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confidence: 99%

Criticality of Tuning in Athermal Phase Transitions

et al. 2009

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We experimentally address the importance of tuning in athermal phase transitions, which are triggered only by a slowly varying external field acting as tuning parameter. Using higher order statistics of fluctuations, a singular critical instability is detected for the first time in spite of an apparent universal self-similar kinetics over a broad range of driving force. The results as well as the experimental technique are likely to be of significance to many slowly driven non-equilibrium systems from geophysics to material science which display avalanche dynamics.In equilibrium statistical physics, continuous phase transitions are critical and are characterized by a diverging correlation length ξ at the critical point. On the other hand, first order transitions are non-critical where the probability of phase transformation is governed by the free energy barrier through the Boltzmann factor [1]. In contrast, athermal first order phase transitions are not influenced by thermal fluctuations and proceed through a set of metastable states of free energy local minima, and hence as the external field (temperature, magnetic field, stress etc.) is varied, display bursty and discrete avalanches [2]. Theoretical models such as random field ising model and the renormalization group analysis [3,4] map these non-equilibrium first order phase transitions to equilibrium critical phenomenon, although the divergence of the correlation length at the critical field has never been clearly demonstrated. Experiments are inconclusive whether these systems self organize to the critical state over a broad range of external field [5,6,7,8,9], or if there exists a unique critical point that is smudged by a wide critical zone as postulated by the concept of "plain-old criticality" [4,10,11]. The bottleneck arises since most experimental claims of critical behavior are based on observation of a scale-free kinetics which causes power law decay in size distribution or the power spectrum of the avalanches [6,9], but none of these are direct probes to ξ itself.In systems with many degrees of freedom [12,13], the non-gaussian component (NGC) in time dependent fluctuations (or noise) in physical observables act as an indicator of long-range correlation between individual fluctuators [14,15]. This has been studied in the context of Barkhausen noise from magnetization avalanches, which probes the role of long-range magnetic interactions in the domain wall depinning when subjected to external magnetic field [16]. Here, we focus on the avalanches in the electrical resistivity, ρ(t), during temperature-driven * electronic mail:chandni@physics.iisc.ernet.in martensite transformation (MT), which is a prototype of athermal phase transition [2]. We demonstrate that the NGC in avalanche induced noise is an extremely sensitive kinetic detector of criticality in continuously driven non-equilibrium systems. We show, for the first time, the existence of a singular 'global instability' [3,10] or divergence of ξ as a function of temperature in MT indicating, (i)...

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“…This, in turn, would introduce significant non-Gaussian components (NGCs) in the resistance fluctuations which can be experimentally probed by studying the higher-order statistics of the measured noise. To test whether the noise in this temperature range originates from glassy dynamics we calculated the fourth moment of voltage fluctuations, what is commonly known in as the "second spectrum" [39][40][41]. Physically, the second spectrum represents the fluctuations in the PSD with time in the chosen frequency octave.…”

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confidence: 99%

Probing the interplay between surface and bulk states in the topological Kondo insulatorSmB6through conductance fluctuation spectroscopy

2017

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We present results of resistance fluctuation spectroscopy on single crystals of the predicted Kondo topological insulator material SmB 6 . Our measurements show that at low temperatures, transport in this system takes place only through surface states. The measured noise in this temperature range arises due to universal conductance fluctuations whose statistics was found to be consistent with theoretical predictions for that of two-dimensional systems in the symplectic symmetry class. At higher temperatures, we find signatures of glassy dynamics and establish that the measured noise is caused by mobility fluctuations in the bulk. We find that, unlike the topological insulators of the dichalcogenide family, the noises in surface and bulk conduction channels in SmB 6 are completely uncorrelated. Our measurements establish that at sufficiently low temperatures, the bulk has no discernible contribution to electrical transport in SmB 6 , making it an ideal platform for probing the physics of topological surface states.

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Non-Gaussian effects in 1/fnoise in small silicon-on-sapphire resistors

Cited by 64 publications

References 8 publications

Correlated Conductance Fluctuations Close to the Berezinskii-Kosterlitz-Thouless Transition in Ultrathin NbN Films

Correlated Conductance Fluctuations Close to the Berezinskii-Kosterlitz-Thouless Transition in Ultrathin NbN Films

Criticality of Tuning in Athermal Phase Transitions

Probing the interplay between surface and bulk states in the topological Kondo insulatorSmB6through conductance fluctuation spectroscopy

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