Direct observation of quantum superconducting fluctuations across the 2D superconductor-insulator transition

Armitage, N. P.; Crane, R.; Sambandamurthy, G.; Johansson, Andreas; Shahar, D.; Zaretskey, V.; Grüner, G.

doi:10.1016/j.physb.2007.10.253

Cited by 2 publications

(3 citation statements)

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“…Finally, the discrepancy between experimental ∆G/G 00 (B) and theoretical dependencies of films with k F l 5 at T/T c < 2 could be eliminated by taking into account possible τ φ dependence on magnetic field [14,21,51]. In this case, calculating β according to equation (5), we obtain the phase breaking rate 1/τ φ (B) that decreases with magnetic field (see figure A3 in appendix). This behavior is in qualitative agreement with theoretical predictions [51].…”

Section: Discussionmentioning

confidence: 98%

“…Now we compare the electron-electron attraction strength β obtained from fitting of ∆G(B) of critically disordered films (β exp ) with theoretical values (β th ) calculated according to equation (5). The ratio β exp /β th for all films is given in figure 4(c).…”

Section: Electron-electron Attraction Strengthmentioning

confidence: 99%

“…Fluctuations play a crucial role in the behavior of disordered superconducting films near the localization threshold [1][2][3][4][5][6]. Superconducting fluctuations (SF) and weak localization (WL) determine the transport properties of the system at low temperatures [7,8].…”

Section: Introductionmentioning

confidence: 99%

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Quantum contributions to the magnetoconductivity of critically disordered superconducting TiN films

Mironov

Postolova

Baturina

2018

J. Phys.: Condens. Matter

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The onset of superconductivity in the presence of disorder is a fundamental problem of condensed matter physics. Here we investigate the magnetoconductance of disordered (8 > k F l > 1.8) superconducting TiN films above the critical temperature T c . We show that the magnetoconductivity of moderately disordered films with k F l > 5 is in full agreement with the perturbative theory of quantum contributions to conductivity. We demonstrate that the magnetoconductivity of films with k F l 5 is also in agreement with the perturbative theory down to temperatures T ≈ 2T c . The quantitative discrepancy between experiment and theory develops only below temperatures T ≈ 2T c for films with k F l 5. This discrepancy can be eliminated if we assume steeper temperature dependence of the Larkin's electron-electron attraction strength, β(T/T c ). The obtained temperature dependence of electron phase breaking time τ ϕ (T/T c ) is in agreement with theoretical predictions for all samples.

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Section: Discussionmentioning

confidence: 98%

Section: Electron-electron Attraction Strengthmentioning

confidence: 99%

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Quantum contributions to the magnetoconductivity of critically disordered superconducting TiN films

Mironov

Postolova

Baturina

2018

J. Phys.: Condens. Matter

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Island formation in disordered superconducting thin films at finite magnetic fields

2008

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It has been predicted theoretically and observed experimentally that disorder leads to spatial fluctuations in the superconducting (SC) gap. Areas where SC correlations are finite, coined SC islands, were shown experimentally to persist into the insulating side of the superconductor-insulator transition. The existence of such (possibly weakly coupled) SC islands in amorphous thin films of superconducting material accounts for numerous experimental findings related to superconductorinsulator transition and non-monotonic magneto-resistance behavior in the insulating region. In this work, a detailed analysis pertaining to the occurrence of SC islands in disordered two-dimensional superconductors is presented. Using a locally self-consistent numerical solution of the Bogoliubovde-Gennes equations, the formation of SC islands is demonstrated, and their evolution with an applied perpendicular magnetic field is studied in some detail, along with the disorder-induced vortex-pinning. While mean-field theory cannot, in principle, explore phase correlations between different islands, it is demonstrated that by inspecting the effect of a parallel magnetic field, one can show that the islands are indeed uncorrelated SC domains. Experimental predictions based on this analysis are presented.

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Direct observation of quantum superconducting fluctuations across the 2D superconductor-insulator transition

Cited by 2 publications

References 10 publications

Quantum contributions to the magnetoconductivity of critically disordered superconducting TiN films

Quantum contributions to the magnetoconductivity of critically disordered superconducting TiN films

Island formation in disordered superconducting thin films at finite magnetic fields

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