Phase fluctuations in conventional superconductors

Raychaudhuri, Pratap; Dutta, Surajit

doi:10.1088/1361-648x/ac360b

Cited by 10 publications

(10 citation statements)

References 195 publications

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“…The approach of this work is based on a mean-field approximation for the complex network of puddles, therefore we point to the importance of considering different topologies for the organization of the puddles and how this can affect not only the transition to the superconducting state [81], but also its possible interplay with the superconducting fluctuations of preformed Cooper pairs observed in the pseudogap phase above T c in cuprates [82], as well as in conventional superconductors such as NbN thin films [83], in terms of local superconductivity. We reinforce that our mean-field treatment is a simplified picture of any actual unconventional superconducting system, since quantum fluctuations are not explicitly included in the calculations, which are known to play a significant role for example in underdoped cuprates and disordered conventional s-wave superconductors [84]. Within the synchronization picture of the network of puddles, these phase fluctuations are accounted for in the picture of local formation of superconducting pairs inside the puddles, as described in [46].…”

Section: Conclusion and Discussionmentioning

confidence: 86%

Gap fluctuations, Cooper pairs with finite center-of-mass momentum, and suppression of superconductivity in inhomogeneous systems with dopant superpuddles agglomerates

Velasco

Neto

2023

J. Phys.: Condens. Matter

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Spatially extended aggregates or clusters of dopants are ubiquitous in a plethora of granular superconducting systems, such as Al-doped MgB2 and N-dopedn Mo2N, forming a droplet network that is very important to their characterization and to the description of their superconducting properties.} At the same time, one of the most studied classes of unconventional superconducting materials are the high-temperature superconductors, where special attention is given to the hole-doped cuprates, where the carrier concentration is controlled by the amount of extra interstitial oxygen dopants. In this context, the formation of spatially inhomogeneous aggregates of interstitial dopant oxygen atoms, in the form of nanosized superpuddles, is not only relevant, but also a subject of intense recent experimental and theoretical surveys. Following these efforts, in this work we investigate the consequences of the presence of networks of {inhomogeneously distributed dopant} superpuddles on the superconducting state. Starting from the inhomogeneous extended disordered background brought by the network of superpuddles, we demonstrate, with the aid of an effective interaction between electrons mediated by the local vibrational degrees of freedom of each puddle, that the Cooper pairs arising from an attractive interaction in an inhomogeneous medium have a finite center-of-mass momentum, p, that breaks up the Cooper channel. Furthermore, we derive an analytical expression for the amplitude of the superconducting gap, △ k , in terms of disorder and finite center-of-mass momentum and show that amplitude fluctuations are induced in the superconducting state by the presence of the superpuddles, where both the gap and the critical temperature are reduced by disorder and finite momentum pairs. Finally, we discuss our findings in the context of {synchronized networks of superconducting oxygen nano-puddles in cuprates and in other granular superconducting systems.

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Section: Conclusion and Discussionmentioning

confidence: 86%

Gap fluctuations, Cooper pairs with finite center-of-mass momentum, and suppression of superconductivity in inhomogeneous systems with dopant superpuddles agglomerates

Velasco

Neto

2023

J. Phys.: Condens. Matter

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“…Being ∆ ≪ J s , the SC transition is thus essentially driven by the suppression of ∆. This scenario holds even in the presence of strong disorder and in partially inhomogeneous systems [38,39]. At the same time, in BCS conventional superconductors, J s ≈ E F (E F being the Fermi energy of the metal) is directly proportional to the number of superfluid carriers n s , with J s ∼ n s /m * , and m * the carrier effective mass.…”

Section: Filamentary Superconductivitymentioning

confidence: 85%

Superfluid response of two-dimensional filamentary superconductors

Venditti,

Maccari,

Jouan

et al. 2023

SciPost Phys.

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Different classes of low-dimensional superconducting systems exhibit an inhomogeneous filamentary superconducting condensate whose macroscopic coherence still needs to be fully investigated and understood. Here, we present a thorough analysis of the superfluid response of a prototypical filamentary superconductor embedded in a two-dimensional metallic matrix. By mapping the system into an exactly solvable random impedance network, we show how the dissipative (reactive) response of the system non-trivially depends on both the macroscopic and microscopic characteristics of the metallic (superconducting) fraction. We compare our calculations with resonant microwave transport measurements performed on LaAlO_33/SrTiO_33 heterostructures over an extended range of temperatures and carrier densities finding that the filamentary character of superconductivity accounts for unusual peculiar features of the experimental data.

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“…The GL theory also gives an estimate of J s and it is considered to be the energy required to twist the phase of a superconductor [71,72]. It is given by:…”

Section: Superconducting Properties: Different Mechanisms At Playmentioning

confidence: 99%

“…Now, PFs can be due to quantum phase fluctuations (QPFs) or thermal phase fluctuations (TPFs). The expression for superfluid density, n s which is proportional to J s for both, is given by [72]:…”

Section: Superconducting Properties: Different Mechanisms At Playmentioning

confidence: 99%

A review of superconductivity in nanostructures—from nanogranular films to anti-dot arrays

Bose¹

2023

Supercond. Sci. Technol.

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Superconductivity in small particles has been studied since the early sixties. A large number of sample geometries for both one component elemental superconductors and dual component nano-composites having elemental superconducting particles dispersed in non-superconductng matrix have been explored which has helped us to understand the mechanism of the evolution of the superconducting transition temperature (Tc) with decreasing particle size. In this article, we review the work done in nano-structured superconductors from nano-granular films to these dual component superconducting nano-composites. In addition, we also present the experimental work done in superconducting films with periodic array of nano-sized holes showing the interesting property of vortex matching effect (VME) and try to understand the dominant mechanism for this phenomena.

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Phase fluctuations in conventional superconductors

Cited by 10 publications

References 195 publications

Gap fluctuations, Cooper pairs with finite center-of-mass momentum, and suppression of superconductivity in inhomogeneous systems with dopant superpuddles agglomerates

Gap fluctuations, Cooper pairs with finite center-of-mass momentum, and suppression of superconductivity in inhomogeneous systems with dopant superpuddles agglomerates

Superfluid response of two-dimensional filamentary superconductors

A review of superconductivity in nanostructures—from nanogranular films to anti-dot arrays

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