Properties of Superconducting Alloys Containing Paramagnetic Impurities

Skalski, S.; Betbeder‐Matibet, O.; Weiß, Peter

doi:10.1103/physrev.136.a1500

Cited by 482 publications

(206 citation statements)

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“…Right inset: Pair breaking parameter Γ used for calculating the IV s and dI/dV s as a function of applied field (symbols) and prediction according to [32,34] (line). The IV at H = 0 was measured at the beginning and the end of the series of measurements and the {Tn} was found to be reproducible.…”

Section: Ivs Of Al Point Contacts With External Magnetic Fieldmentioning

confidence: 99%

“…A quantitative description of the influence of the magnetic field is difficult because of the complicated shape of [34]) and position of the m = 1 maximum of the corresponding calculated dI/dV s (symbols) in units of the gap parameter at zero field as a function of the pair breaking parameter Γ. Right inset: Pair breaking parameter Γ used for calculating the IV s and dI/dV s as a function of applied field (symbols) and prediction according to [32,34] (line).…”

Section: Ivs Of Al Point Contacts With External Magnetic Fieldmentioning

confidence: 99%

“…The fact that all signature of superconductivity is destroyed at the bulk critical field indicates that the geometry of the sample does not play a dominant role, but that ξ is the most important length scale. We therefore describe the influence of the magnetic field along the lines of Skalski et al [34] using a homogeneous Γ given by the expression [32,35] …”

Section: Ivs Of Al Point Contacts With External Magnetic Fieldmentioning

confidence: 99%

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Conduction channels of superconducting quantum point contacts

Scheer

Cuevas

Yeyati

et al. 2000

Physica B: Condensed Matter

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Esta es la versión de autor del artículo publicado en: This is an author produced version of a paper published in: El acceso a la versión del editor puede requerir la suscripción del recurso Access to the published version may require subscription Atomic quantum point contacts accommodate a small number of conduction channels. Their number N and transmission coefficients {Tn} can be determined by analyzing the subgap structure due to multiple Andreev reflections in the current-voltage (IV ) characteristics in the superconducting state.With the help of mechanically controllable break-junctions we have produced Al contacts consisting of a small number of atoms. In the smallest stable contacts, usually three channels contribute to the transport. We show here that the channel ensemble {Tn} of few atom contacts remains unchanged up to temperatures and magnetic fields approaching the critical temperature and the critical field, respectively, giving experimental evidence for the prediction that the conduction channels are the same in the normal and in the superconducting state.

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Section: Ivs Of Al Point Contacts With External Magnetic Fieldmentioning

confidence: 99%

Section: Ivs Of Al Point Contacts With External Magnetic Fieldmentioning

confidence: 99%

Section: Ivs Of Al Point Contacts With External Magnetic Fieldmentioning

confidence: 99%

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Conduction channels of superconducting quantum point contacts

Scheer

Cuevas

Yeyati

et al. 2000

Physica B: Condensed Matter

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“…It is suppressed to ϳ50% at B Ќ = 30 mT and B ʈ = 300 mT as indicated by the vertical dotted lines. The field B ʈ exceeds B Ќ by an order of magnitude but is still a factor of five smaller than needed for an appreciable reduction in the gap ⌬ Nb ͑B͒ as follows from the pair-breaking theory 18 ͑right dotted line in Fig. 4͒.…”

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confidence: 99%

Doppler shift in Andreev reflection from a moving superconducting condensate in Nb/InAs Josephson junctions

et al. 2009

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We study narrow ballistic Josephson weak links in a InAs quantum wells contacted by Nb electrodes and find a dramatic magnetic-field suppression of the Andreev reflection amplitude, which occurs even for in-plane field orientation with essentially no magnetic flux through the junction. Our observations demonstrate the presence of a Doppler shift in the energy of the Andreev levels, which results from diamagnetic screening currents in the hybrid Nb/InAs banks. The data for conductance, excess, and critical currents can be consistently explained in terms of the sample geometry and the McMillan energy, characterizing the transparency of the Nb/InAs interface. DOI: 10.1103/PhysRevB.80.220507 PACS number͑s͒: 74.45.ϩc In recent years a detailed microscopic understanding of the proximity effect has emerged. There is now agreement that in highly transparent Josephson junctions formed by a metallic weak link in good contact with two superconducting ͑SC͒ banks the supercurrent is carried by Andreev bound states ͑ABSs͒. 1 These come in pairs corresponding to the opposite directions of Cooper-pair transfer mediated by multiple Andreev reflection ͑MAR͒ at the SC/metal interfaces provided that the acquired quasiparticle phase is a multiple of 2 . 2 At currents exceeding the critical current I C ͑T , B͒ MAR between the SC banks manifests itself in the currentvoltage characteristics as subharmonic gap structures at voltages eV n =2⌬ / n, where ⌬ is the SC energy gap and n =1,2,.... At higher voltage eV ӷ 2⌬, I͑V͒ becomes linear with an excess current I exc = I͑V͒ − G N V determined by a single Andreev reflection ͑AR͒ probability ͉a͑ ͉͒ 2 ͑G N is the normal-state conductance͒. 3,4 Weak links formed by a two-dimensional ͑2D͒ electron gas ͑2DEG͒ in semiconductor quantum wells 5 are of particular interest because here the ballistic transport can be studied. In very high magnetic field perpendicular to the 2DEG, theory 6 and experiments 7,8 have demonstrated Andreev transport via edge states. Indirect evidence for a strong magneticfield effect on AR was experimentally found in antidot billiards. 9 The case of parallel field, with respect to the 2DEG, is equally intriguing: as ideally no magnetic flux threads the 2DEG, one may naively expect the Josephson current to survive up to the critical fields of the SC leads. This is not the case, but the underlying mechanism of the supercurrent suppression is still unclear. This question, also relevant for other 2D hybrid systems, 10 is among the issues this Rapid Communication focuses on.In this Rapid Communication, Nb/InAs Josephson junctions of different width are studied in a four-terminal lead configuration within the 2DEG. This allows us to separately determine the transparencies of the InAs weak link and Nb/ InAs interfaces and identify an additional energy scale in the electronic spectrum of the hybrid SC terminals. We observe a very strong suppression of both the AR probability and supercurrent in weak magnetic fields of 4 and 100 mT for perpendicular and parallel orientations, r...

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“…Taking, first, the diffusion limit with ξ well exceeding the mean free path , we find (see Refs. [20][21][22]…”

mentioning

confidence: 99%