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Pannetier, B.; Courtois, Hervé

doi:10.1023/a:1004635226825

Cited by 189 publications

(131 citation statements)

References 61 publications

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“…The proximity effect in normal metal-superconducting structures has been known for a long time [1,2] but still is a subject of intense theoretical and experimental research [3,4]. The most prominent manifestation of the proximity effect is a supercurrent flowing through a normal metal between distant superconducting electrodes.…”

Section: Supercurrents In Unidirectional Channels Originate From Infomentioning

confidence: 99%

Supercurrents in Unidirectional Channels Originate from Information Transfer in the Opposite Direction: A Theoretical Prediction

Huang

Nazarov

2017

Phys. Rev. Lett.

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It has been thought that the long chiral edge channels cannot support any supercurrent between the superconducting electrodes. We show theoretically that the supercurrent can be mediated by a non-local interaction that facilitates a long-distance information transfer in the direction opposite to electron flow. We compute the supercurrent for several interaction models, including that of an external circuit.

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Section: Supercurrents In Unidirectional Channels Originate From Infomentioning

confidence: 99%

Supercurrents in Unidirectional Channels Originate from Information Transfer in the Opposite Direction: A Theoretical Prediction

Huang

Nazarov

2017

Phys. Rev. Lett.

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“…Superconductor coupled to a normal conductor has been studied with respect to superconducting proximity effect and Andreev reflection for few decades [1]. A Cooper pair can penetrate into a normal conductor with a decay length.…”

Section: Introductionmentioning

confidence: 99%

“…For the property of electron transport, the SWNT belongs to a ballistic transport and network-like SWNTs shall become a quasi-diffusive transport. Some phenomena occurring in the normal conductor of diffusive transport adjacent to a superconductor, such as reflectionless tunnelling and reentrant behavior, are due to the interplay between quantum transport in the metallic state and the superconducting state effect from the superconducting reservoir [1,10]. We have studied the S/network-like SWNTs/S junctions in diffusive regime.…”

Section: Introductionmentioning

confidence: 99%

Superconducting proximity effect in single-walled carbon nanotubes between NbN electrodes

Zhong

Akazak

Kanzaki

et al. 2006

Science and Technology of Advanced Materials

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We have fabricated network-like single-walled carbon nanotubes with superconducting NbN electrodes. The single-wall carbon nanotubes were synthesized on SiO 2 substrates by the thermal chemical vapor deposition technique using Co catalyst. We obtained sufficiently good contact characteristics between the single-walled carbon nanotubes and the NbN electrodes by infrared annealing at heater temperature 700 C for $15 min in vacuum. We observed multiple Andreev reflection by measuring differential resistance as a function of applied voltage below 7 K. This multiple Andreev reflection is due to the proximity effect between NbN electrodes. The superconducting energy gap of NbN, 2D, is about 6 meV. The multiple Andreev reflection processes occur around the dips, i.e. AE2D=e and AED=e. On the other hand, at above 8 K, the curves of different resistance are changed from dip to peak at zero bias voltage. This behavior is similar to reentrant behavior that has a maximum conductance corresponding to the correlation energy (Thouless energy) below superconducting critical temperature T c . This reentrant behavior has been studied in normal metal or two-dimensional gas of semiconductor heterostructures coupled to superconductor. r

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“…In the Usadel equations, all physical quantities only involve the intrinsic combination − → ∇ϕ − (2e/ ) A, where the gradient − → ∇ϕ in the phase of the superconducting order parameter is associated with the supercurrent, revealing the equivalence of a supercurrent and of an applied magnetic field. The Usadel equations are now at the basis of the understanding of mesoscopic superconductivity in diffusive conductors [5,6]. Experimentally, measurements of the density of states (DOS) in a thin superconductor placed in an in-plane magnetic field were well accounted for by the concept of depairing energy [7].…”

mentioning

confidence: 99%

Density of States in a Superconductor Carrying a Supercurrent

2003

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We have measured the tunneling density of states (DOS) in a superconductor carrying a supercurrent or exposed to an external magnetic field. The pair correlations are weakened by the supercurrent, leading to a modification of the DOS and to a reduction of the gap. As predicted by the theory of superconductivity in diffusive metals, we find that this effect is similar to that of an external magnetic field.PACS numbers: PACS numbers: 74.78. Na, 74.20.Fg, 74.25.Sv How is the superconducting order modified by a supercurrent? The superconducting order is based on pairing electronic states which transform into one another by time reversal [1]. The ground-state wavefunction corresponds to a coherent superposition of doubly empty and doubly occupied time-reversed states, in an energy range around the Fermi level given by the BCS gap energy. When an external magnetic field B = curl A is applied, time-reversed states are dephased differently, resulting in a weakening of superconductivity. In presence of a supercurrent, the superconducting order no longer corresponds to the pairing of time-reversed states, which results in a kinetic energy cost, and again in a weakening of superconductivity. In the early stages of the theory of superconductivity, it was found that, in diffusive superconductors (in which the electron mean-free-path is short compared to the BCS coherence length) and in homogeneous situations, the modification of the superconducting order by a magnetic field, by a current and by paramagnetic impurities could be described by a single parameter, the depairing energy Γ [2]. Later on, the reformulation of the theory by Usadel [3,4] in the diffusive limit extended this equivalence to inhomogeneous situations, where the modulus of the order parameter may vary in space. In the Usadel equations, all physical quantities only involve the intrinsic combination − → ∇ϕ − (2e/ ) A, where the gradient − → ∇ϕ in the phase of the superconducting order parameter is associated with the supercurrent, revealing the equivalence of a supercurrent and of an applied magnetic field. The Usadel equations are now at the basis of the understanding of mesoscopic superconductivity in diffusive conductors [5,6]. Experimentally, measurements of the density of states (DOS) in a thin superconductor placed in an in-plane magnetic field were well accounted for by the concept of depairing energy [7]. In contrast, the effect of a supercurrent has been partly addressed in a single experiment, focused on the reduction of the superconducting gap close to the critical temperature [8]. A complication of the experiments with a supercurrent is that, if the sample width exceeds the London penetration length λ L , the current distribution given by the non-local equations of electrodynamics [9] is not homogeneous. In the experiment reported here, the superconductor is wire-shaped, with thickness and width smaller than λ L , so that the current flow is homogeneous and the magnetic field penetrates completely. Moreover, the effect of the magnetic field ind...

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Cited by 189 publications

References 61 publications

Supercurrents in Unidirectional Channels Originate from Information Transfer in the Opposite Direction: A Theoretical Prediction

Supercurrents in Unidirectional Channels Originate from Information Transfer in the Opposite Direction: A Theoretical Prediction

Superconducting proximity effect in single-walled carbon nanotubes between NbN electrodes

Density of States in a Superconductor Carrying a Supercurrent

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