Weakly non-Gaussian processes in a-Si:H conductance noise

Abkemeier, Kristin M.

doi:10.1103/physrevb.55.7005

Cited by 21 publications

(4 citation statements)

References 27 publications

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“…Therefore, the value of the exponent (1 − β) is a convenient measure of the non-Gaussian character of the noise. S 2 was analyzed by using digital filtering 36,37 in a given frequency range f = (f L , f H ) (usually f H = 2f L ). Some examples of the normalized S 2 (f 2 ), with the Gaussian background subtracted, are presented in Fig.…”

Section: Dependence Of Conductance Noise On Applied Electric Fieldmentioning

confidence: 99%

Conductance noise in an out-of-equilibrium two-dimensional electron system

et al. 2012

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A study of the conductance noise in a two-dimensional electron system (2DES) in Si at low temperatures (T ) reveals the onset of large, non-Gaussian noise after cooling from an equilibrium state at a high T with a fixed carrier density ns. This behavior, which signifies the falling out of equilibrium of the 2DES as T → 0, is observed for ns < ng (ng -glass transition density). A protocol where density is changed by a small value ∆ns at low T produces the same results for the noise power spectra. However, a detailed analysis of the non-Gaussian probability density functions (PDFs) of the fluctuations reveals that ∆ns has a qualitatively different and more dramatic effect than ∆T , suggesting that ∆ns induces strong changes in the free energy landscape of the system as a result of Coulomb interactions. The results from a third, waiting-time (tw) protocol, where ns is changed temporarily during tw by a large amount, demonstrate that non-Gaussian PDFs exhibit history dependence and an evolution towards a Gaussian distribution as the system ages and slowly approaches equilibrium. By calculating the power spectra and higher-order statistics for the noise measured over a wide range of the applied voltage bias, it is established that the non-Gaussian noise is observed in the regime of Ohmic or linear response, i.e. that it is not caused by the applied bias.

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Section: Dependence Of Conductance Noise On Applied Electric Fieldmentioning

confidence: 99%

Conductance noise in an out-of-equilibrium two-dimensional electron system

et al. 2012

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“…44,46,47 The second spectra have been calculated using digital filtering. 48,49 First, the fast Fourier transform (FFT) is applied to the data, which are then digitally bandpass filtered in a given frequency range f = (f L , f H ) with f H = 2f L . This allows the analysis of ∆R(t)/ R in any bandpass.…”

Section: Higher-order Statisticsmentioning

confidence: 99%

Non-Gaussian noise in the in-plane transport of lightly doped La2−xSrxC

et al. 2011

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A study of the in-plane resistance noise on a high quality single crystal of La1.97Sr0.03CuO4 deep inside the spin-glass phase reveals the onset of non-Gaussianity and the insensitivity of the noise to the in-plane magnetic field. The results indicate that the charge dynamics becomes increasingly slow and correlated as temperature T → 0. The analysis of the higher order noise statistics provides evidence for the existence of a collective ground state of charge clusters, which seem to coexist with charge-poor antiferromagnetic domains that are frozen at such low T .

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“…As is seen, if there were no correlation in the measured signal, 82 would be proportional to square of the first spectrum. It has been shown [13,25,26] that if the second spectrum is flat, i.e., its magnitude does not depend on frequency, the relevant fluctuators are uncorellated as in the case of the droplet excitations. In contrast, 82 α 1/fó with the exponent δ 1 means that noise comes from the pool of wandering events.…”

Section: Resultsmentioning

confidence: 99%

Transport in Quantum Structures of Diluted Magnetic Semiconductors

Jaroszyński

1999

Acta Phys. Pol. A

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. This paper reviews recent millikelvin studies of magnetoconductance and noise in nanostructures of a diluted magnetic semiconductor n-Cd 1-x Mnx Te. These studies were particularly rewarding for probing the influence of magnetic ions upon mesoscopic phenomena. The accumulated results demonstrated the existence of a new driving mechanism of the universal conductance fluctuations in magnetic systems. Several signatures of spin-glass freezing were observed, such as the appearance of 1/f conductance noise, aging, thermal, and magnetic irreversibilities as well as a strong increase in the amplitude of both conductance fluctuations and noise when temperature and the magnetic field were lowered below the freezing line. A statistical analysis of conductance noise made it possible to investigate the nature of excitations in spin-glass phase, and to discriminate between competing theoretical models.

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Weakly non-Gaussian processes in a-Si:H conductance noise

Cited by 21 publications

References 27 publications

Conductance noise in an out-of-equilibrium two-dimensional electron system

Conductance noise in an out-of-equilibrium two-dimensional electron system

Non-Gaussian noise in the in-plane transport of lightly doped La2−xSrxC

Transport in Quantum Structures of Diluted Magnetic Semiconductors

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