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We experimentally study the influence of 1-40 GHz radiation on the resistance of normal (N) mesoscopic conductors coupled to superconducting (S) loops (Andreev interferometers). At low RF amplitudes we observe the usual h/2e…

Mesoscale and Nanoscale Physics · Physics 2010-03-11 C. Checkley , A. Iagallo , R. Shaikhaidarov , J. T. Nicholls , V. T. Petrashov

Using the tight binding model and the non-equilibrium Green function method, we study Andreev reflection in graphene-superconductor junction, where graphene has two nonequal Dirac Cones split in energy and therefore time reversal symmetry…

Superconductivity · Physics 2020-01-15 Chao Wang , Lin Zhang , Peipei Zhang , Juntao Song , Yu-Xian Li

A theory of coherent multiple Andreev reflections (MAR) is developed for superconductor-normal metal-superconductor (SNS) interferometers. We consider a Y-shape normal electron beam splitter connecting two superconducting reservoirs, where…

Superconductivity · Physics 2009-11-07 J. Lantz , V. S. Shumeiko , E. Bratus , G. Wendin

We analyze the charge transport between a one-dimensional weakly interacting electron gas and a superconductor within the scaling approach in the basis of scattering states. We derive the renormalization group equations, which fully account…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 M. Titov , M. Mueller , W. Belzig

With the aid of the Keldysh effective action technique we develop a microscopic theory describing Andreev level spectroscopy experiments in non-tunnel superconducting contacts. We derive an effective impedance of such contacts which…

Superconductivity · Physics 2016-01-20 Artem V. Galaktionov , Andrei D. Zaikin

The stationnary Josephson effect in a clean Superconductor-Ferromagnet-Superconductor junction is revisited for arbitrarily large spin polarizations. The quasiclassical calculation of the supercurrent assumes that the Andreev reflection is…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 J. Cayssol , G. Montambaux

We investigate the Andreev reflection and Josephson effect in the $\alpha$-T3 lattice which falls between graphene ($\alpha = 0$) and the dice lattice ($\alpha = 1$) by adjusting the parameter $\alpha$. In the regime of specular Andreev…

Mesoscale and Nanoscale Physics · Physics 2021-10-04 Xingfei Zhou

We propose that, if the pseudogap state in the cuprate superconductors can be described in terms of the phase-incoherent preformed pairs, there should exist Andreev reflection from these pairs even above the superconducting transition…

Superconductivity · Physics 2009-10-31 Han-Yong Choi , Yunkyu Bang , David K. Campbell

Resonant Andreev reflection through superconductor-carbon-nanotube devices was investigated theoretically with a focus on the superconducting proximity effect. Consistent with a recent experiment, we find that for high transparency devices…

Condensed Matter · Physics 2009-11-07 Yadong Wei , Jian Wang , Hong Guo , Hatem Mehrez , R. Roland

Andreev bound states (ABS) occur in Josephson junctions when the total phase of the Andreev and normal reflections is a multiple of $2\pi$. In ballistic junctions with an applied voltage bias, a quasi-particle undergoes multiple Andreev…

Superconducting micro-constrictions between Nb tips and high quality MgB$_{2}$ pellets have been realized by means of a point-contact inset, driven by a micrometric screw. Measurements of the current-voltage characteristics and of the…

We experimentally study the influence of 1-40 GHz radiation on the resistance of normal (N) mesoscopic conductors coupled to superconducting (S) loops (Andreev interferometers). At low RF amplitudes we observe the usual h/2e…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 C. Checkley , A. Iagallo , R. Shaikhaidarov , J. T. Nicholls , V. T. Petrashov

As charge carriers traverse a single superconductor ferromagnet interface they experience an additional spin-dependent phase angle which results in spin mixing and the formation of a bound state called the Andreev Bound State. This state is…

Superconductivity · Physics 2017-03-29 K. A. Yates , D. Prabhakaran , M. Egilmez , J. W. A. Robinson , L. F. Cohen

The influence of electron reflection on dc Josephson effect in a ballistic point contact with transport current in the banks is considered theoretically. The effect of finite transparency on the vortex-like currents near the contact and at…

Superconductivity · Physics 2009-11-10 G. Rashedi , Yu. A. Kolesnichenko

We measure the excitation spectrum of a superconducting atomic contact. In addition to the usual continuum above the superconducting gap, the single particle excitation spectrum contains discrete, spin-degenerate Andreev levels inside the…

Mesoscale and Nanoscale Physics · Physics 2014-01-07 L. Bretheau , C. O. Girit , C. Urbina , D. Esteve , H. Pothier

We consider a process of the Andreev reflection between a normal metal and the s-wave superconductor in the FFLO state. It is shown that the process takes place if the energy of the incoming electron is bound within the finite interval…

Superconductivity · Physics 2015-05-13 Tomasz L. Partyka , Mariusz Sadzikowski , Motoi Tachibana

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

Reflection of charge excitations at the step in the interaction strength in a Luttinger liquid can be of the Andreev type, even if the interactions are purely repulsive. The region with stronger repulsion plays the role of a normal metal in…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 Dmitrii L. Maslov , Paul M. Goldbart

We show that irradiation of a voltage-biased superconducting quantum point contact at frequencies of the order of the gap energy can remove the suppression of subgap dc transport through Andreev levels. Quantum interference among resonant…

Superconductivity · Physics 2009-10-31 N. I. Lundin , L. Y. Gorelik , R. I. Shekhter , V. S. Shumeiko , M. Jonson

An overview is presented of experiments on ballistic electrical transport in inhomogeneous superconducting systems which are controlled by the process of Andreev reflection. The initial experiments based on the coexistence of a normal phase…

Superconductivity · Physics 2015-06-22 T. M. Klapwijk , S. A. Ryabchun