Low-Frequency Noise Probe of Interacting Charge Dynamics in Variable-Range Hopping Boron-Doped Silicon

Massey, J. G.; Lee, Mark

doi:10.1103/physrevlett.79.3986

Cited by 31 publications

(40 citation statements)

References 21 publications

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“…While leading to 1/ f -type noise within some frequency range, this model also shows low frequency noise saturation due to the exponentially small probability of finding an isolated pair of sites with a long tunneling time. Moreover, the noise magnitude is predicted to increase as the temperature T → 0 in contradiction with the recent experimental findings of Massey and Lee [11]. This, in part, led Massey and Lee to the conclusion that the single particle picture is inconsistent with the observed noise behavior.…”

Section: Introductionmentioning

confidence: 57%

1/fnoise in electron glasses

Shtengel

2003

Phys. Rev. B

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We show that 1/ f noise is produced in a 3D electron glass by charge fluctuations due to electrons hopping between isolated sites and a percolating network at low temperatures. The low frequency noise spectrum goes as ω −α with α slightly larger than 1. This result together with the temperature dependence of α and the noise amplitude are in good agreement with the recent experiments. These results hold true both with a flat, noninteracting density of states and with a density of states that includes Coulomb interactions. In the latter case, the density of states has a Coulomb gap that fills in with increasing temperature. For a large Coulomb gap width, this density of states gives a dc conductivity with a hopping exponent of ≈ 0.75 which has been observed in recent experiments. For a small Coulomb gap width, the hopping exponent ≈ 0.5.

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Section: Introductionmentioning

confidence: 57%

1/fnoise in electron glasses

Shtengel

2003

Phys. Rev. B

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“…Quite strikingly, for the same set of materials (PbIn/Nb for the SQUID's loop/electrode) and depending on the construction, the flux noise can be either completely independent of temperature or inversely proportional to it or even oscillate with temperature. Such conflicting temperature dependencies of 1/f noise are known to exist for glassy systems [35,36].…”

Section: Within a Single Cluster The Spins Interact Via An Oscillatomentioning

confidence: 99%

Ising-Glauber Spin Cluster Model for Temperature-Dependent Magnetization Noise in SQUIDs

2014

Phys. Rev. Lett.

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Clusters of interacting two-level-systems (TLS),likely due to F+ centers at the metal-insulator interface, are shown to self consistently lead to 1/f α magnetization noise in SQUIDs. By introducing a correlation-function calculation method and without any a priori assumptions on the distribution of fluctuation rates, it is shown why the flux noise is only weakly temperature dependent with α < ∼ 1, while the inductance noise has a huge temperature dependence seen in experiment, even though the mechanism producing both spectra is the same. Though both ferromagnetic-RKKY and short-range-interactions (SRI) lead to strong flux-inductance-noise cross-correlations seen in experiment, the flux noise varies a lot with temperature for SRI. Hence it is unlikely that the TLS's time reversal symmetry is broken by the same mechanism which mediates surface ferromagnetism in nanoparticles and thin films of the same insulator materials. PACS numbers: 85.25.Dq, 03.67.Lx Superconducting quantum interference devices (SQUID) are of considerable interest for quantum information as they can replicate natural qubits, such as electron and nuclear spins, using macroscopic devices. However the performance of superconducting qubits is severely impeded by the presence of 1/f magnetization noise which limits their quantum coherence. This type of noise was first observed in SQUIDs well over two decades ago [1,2], however its origins and many of its features remain unexplained. Recent activity in quantum computing has however revived interests to better understand this magnetization noise. [3,4].Magnetic noise in SQUIDs has several puzzling features. While the flux noise (the first spectrum) is also weakly dependent on temperature, the choice of the superconducting material and the SQUID's area [1,5,6] -the inductance noise (the second spectrum or the noise of the flux noise), surprisingly shows a strong temperature dependence. It decreases with increasing temperature and scales as 1/f α [5] where the temperature dependent (0 < α(T ) < 1) [7]. The flux noise is also known to be only weakly dependent on geometry and the noise scales as l/w, in the limit w/l << 1 (l is the length and w is the width of the superconducting wire) [8]. This along with recent experiments [5] suggests that flux noise arises from unpaired surface spins which reside at the Experimental evidence also suggests that these surface spins are strongly interacting and that there is a net spin polarization [5] as the 1/f inductance noise is highly correlated with the usual 1/f flux noise. This cross-correlation is inversely proportional to the temperature and is about the order of unity roughly below 100mK. Since inductance is even under time inversion and flux is odd, their three-point crosscorrelation function must vanish unless time reversal symmetry is broken, which indicates the appearance of long range magnetic order. As this further implies that the mechanism producing both the flux-and inductance noise is the same, it is not clear on why only the associated spectrum ...

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“…Electron glasses are no exception, and various experimental studies have measured 1/f noise in such systems [66][67][68][69][70][71][72]. An even larger amount of work has been invested in the theoretical aspects of this problem.…”

Section: B Noise In Electron Glassesmentioning

confidence: 99%

Electron Glass Dynamics

Amir

Oreg

Imry

2011

Annu. Rev. Condens. Matter Phys.

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Examples of glasses are abundant, yet it remains one of the phases of matter whose understanding is very elusive. In recent years, remarkable experiments have been performed on the dynamical aspects of glasses. Electron glasses offer a particularly good example of the 'trademarks' of glassy behavior, such as aging and slow relaxations. In this work we review the experimental literature on electron glasses, as well as the local mean-field theoretical framework put forward in recent years to understand some of these results. We also present novel theoretical results explaining the periodic aging experiment.Comment: Invited review to appear in Annual Review of Condensed Matter Physic

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Low-Frequency Noise Probe of Interacting Charge Dynamics in Variable-Range Hopping Boron-Doped Silicon

Cited by 31 publications

References 21 publications

1/fnoise in electron glasses

1/fnoise in electron glasses

Ising-Glauber Spin Cluster Model for Temperature-Dependent Magnetization Noise in SQUIDs

Electron Glass Dynamics

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