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By measuring the shot noise, a consequence of charge quantization, in superconductor/insulator/ferromagnet (V/MgO/Fe) junctions, we discover a giant increase, orders of magnitude larger than expected. The origin of this giant noise is a…

We have examined the electrical behavior of Josephson junctions formed by a scanning tunneling microscope (STM) with a Nb sample and a Nb tip, with normal-state resistances Rn varying between 1 kOhm and 10 MOhm. Current-voltage…

Superconductivity · Physics 2026-01-16 Wan-Ting Liao , S. K. Dutta , R. E. Butera , C. J. Lobb , F. C. Wellstood , M. Dreyer

The low-frequency shot-noise power of a normal-metal-superconductor junction is studied for arbitrary normal region. Through a scattering approach, a formula is derived which expresses the shot-noise power in terms of the transmission…

Condensed Matter · Physics 2007-05-23 M. J. M. de Jong , C. W. J. Beenakker

We determine the quasi-particle excitation spectrum in the normal region of a narrow ballistic superconductor--normal-metal--superconductor (SNS) Josephson contact. Increasing the effective chemical potential in the contact converts the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Nikolai M. Chtchelkatchev , Gordey B. Lesovik , Gianni Blatter

Employing quasiclassical theory of superconductivity combined with Keldysh technique we investigate large thermoelectric effect in multiterminal ballistic normal-superconducting (NS) hybrid structures. We argue that this effect is caused by…

Superconductivity · Physics 2017-02-01 Mikhail S. Kalenkov , Andrei D. Zaikin

We study the current noise spectra of a tunnel junction of a metal with strong pairing phase fluctuation and a superconductor. It is shown that there is a characteristic peak in the noise spectrum at the intrinsic Josephson frequency…

Strongly Correlated Electrons · Physics 2009-10-31 Xi Dai , Tao Xiang , Tai-Kai Ng , Zhao-bin Su

We investigate transport properties of ballistic magnetic Josephson junctions and establish that suppression of supercurrent is an intrinsic property of the junctions, even in absence of disorder. By studying the role of ferromagnet…

Mesoscale and Nanoscale Physics · Physics 2022-01-31 Hervé Ness , Ivan A. Sadovskyy , Andrey E. Antipov , Mark van Schilfgaarde , Roman M. Lutchyn

The effect of dc electrical stress and breakdown on Josephson and quasiparticle tunneling in Nb/Al/AlOx/Nb junctions with ultrathin AlOx barriers typical for applications in superconductor digital electronics has been investigated. The…

Superconductivity · Physics 2015-01-05 Sergey K. Tolpygo , Denis Amparo

We have studied the origin of excess noise in superconducting transition-edge sensors (TES) with several different detector designs. We show that most of the observed noise and complex impedance features can be explained by a thermal model…

Superconductivity · Physics 2015-03-19 K. M. Kinnunen , M. R. J. Palosaari , I. J. Maasilta

In the "ballistic" regime, the transport across a normal metal (N)/superconductor (S) point-contact is dominated by a quantum process called Andreev reflection. Andreev reflection causes an enhancement of the conductance below the…

Superconductivity · Physics 2021-10-04 Ritesh Kumar , Goutam Sheet

We present theoretical calculations and predictions for the shot noise in voltage biased junctions of $d_{x^2-y^2}$ superconductors and normal metal counter-electrodes. In the clean limit for the d-wave superconductor the shot noise…

Superconductivity · Physics 2009-11-10 Tomas Lofwander , Mikael Fogelstrom , J. A. Sauls

We investigated the electrical transport properties of superconductor-graphene-superconductor (SGS) Josephson junctions. In low voltage bias, we observed conventional proximity-coupled Josephson effect, such as the supercurrent flow through…

Mesoscale and Nanoscale Physics · Physics 2011-02-23 Jae-Hyun Choi , Hu-Jong Lee , Yong-Joo Doh

The subgap conductivity of a normal-superconductor (NS) tunnel junction is thought to be due to tunneling of two electrons. There is a strong interference between these two electrons, originating from the spatial phase coherence in the…

Condensed Matter · Physics 2009-10-22 F. W. J. Hekking , Yu. V. Nazarov

We have measured the conductance and shot-noise of superconductor-normal metal (S-N) junctions between a Niobium (Nb) film and a 2-dimensional electron gas (2DEG), formed in an InAs-based semiconductor heterostructure. Adjacent to the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 B. -R. Choi , A. E. Hansen , T. Kontos , C. Hoffmann , S. Oberholzer , W. Belzig , C. Schoenenberger , T. Akazaki , H. Takayanagi

Tunnel junction between two superconductors is considered in the vicinity of the critical temperature. Superconductive fluctuations above Tc give rise to the noise of the ac Josephson current although the current itself is zero in average.…

Superconductivity · Physics 2009-11-13 Alex Levchenko

The Josephson Effect and Superconducting Proximity Effect were observed in Superconductor -Graphene-Superconductor (SGS) Josephson junctions with coherence lengths comparable to the distance between the superconducting leads. By comparing…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Xu Du , Ivan Skachko , Eva Y. Andrei

We consider a Josephson contact mediated by 1D chiral modes on a surface of a 3D topological insulator with superimposed superconducting and magnetic layers. The system represents an interferometer in which 1D chiral Majorana modes on the…

Superconductivity · Physics 2018-12-06 Dmitriy S. Shapiro , Alexander D. Mirlin , Alexander Shnirman

We investigate the properties of subharmonic gap structure (SGS) in superconducting quantum contacts with normal-electron resonances. We find two distinct new features of the SGS in resonant junctions which distinguish them from…

Superconductivity · Physics 2009-10-31 G. Johansson , E. N. Bratus , V. S. Shumeiko , G. Wendin

Non-equilibrium excess noise of a short quasi one-dimensional constriction between two superconductors is considered. A general expression for the current-current correlation function valid for arbitrary temperatures and bias voltages is…

Condensed Matter · Physics 2009-10-28 J. P. Hessling , V. S. Shumeiko , Yu. M. Galperin , G. Wendin

We report on the low frequency noise in the ballistic point-contacts between a silver tip and a niobium foil. The ballistic nature of the point-contacts is confirmed by Andreev reflection spectroscopy at low bias voltage with the Nb foil…

Superconductivity · Physics 2014-10-15 Jian Wei , Goutam Sheet , Venkat Chandrasekhar