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We calculate the conductance through double junctions of the type M(inf.)-Sn-Mm-Sn-M(inf.) and triple junctions of the type M(inf.)-Sn-Mm-Sn-Mm-Sn-M(inf.), where M(inf.) are semi-infinite metallic electrodes, Sn are 'n' layers of…

Mesoscale and Nanoscale Physics · Physics 2008-10-03 J. Peralta-Ramos , A. M. Llois

Structural disorder is present in almost all experimental measurements of electronic transport through single molecules or molecular wires. To assess its influence on the conductance is computationally demanding, because a large number of…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 R. Maul , W. Wenzel

We show theoretically that quantized zero-bias conductance peaks should be ubiquitous in superconductor-semiconductor hybrids by employing a zero-dimensional random matrix model with continuous tuning parameters. We demonstrate that a…

Mesoscale and Nanoscale Physics · Physics 2020-01-15 Haining Pan , William S. Cole , Jay D. Sau , S. Das Sarma

Coherent electron transport through a quantum channel in the presence of a general extended scattering potential is investigated using a T-matrix Lippmann-Schwinger approach. The formalism is applied to a quantum wire with Gaussian type…

The conductance of a junction between a normal metal and a superconductor having the symmetry proposed by Berezinskii is studied theoretically. The main feature of this symmetry is the odd frequency dependence of the anomalous Green…

Superconductivity · Physics 2008-03-15 Ya. V. Fominov

Experiments on hybrid superconducting normal-metal structures have revealed that even in the absence of tunnel junctions the onset of superconductivity can lead to a decrease in the electrical conductance by an amount many orders of…

Superconductivity · Physics 2007-05-23 R. Seviour , C. J. Lambert , M. Leadbeater

We show that in contrast to conventional normal metal-insulator-superconductor (NIS) junctions, the tunneling conductance of a NIS junction in graphene is an oscillatory function of the effective barrier strength of the insulating region,…

Superconductivity · Physics 2009-11-11 Subhro Bhattacharjee , K. Sengupta

Devices made of few molecules constitute the miniaturization limit that both inorganic and organic-based electronics aspire to reach. However, integration of millions of molecular junctions with less than 100 molecules each has been a long…

Mesoscale and Nanoscale Physics · Physics 2013-02-11 Kacem Smaali , Nicolas Clement , Gilles Patriarche , Dominique Vuillaume

Charge transport in a high-transmission single-mode long SINIS junction (S stands for superconductor, I is an insulator, and N is a normal metal) is considered in the limit of low bias voltages and low temperatures. The kinetic equation for…

Superconductivity · Physics 2007-05-23 N. B. Kopnin J. Voutilainen

A conceptual consideration is given to a zero-energy state (ZES) at the surface of unconventional superconductors. The reflection coefficients in normal-metal / superconductor (NS) junctions are calculated based on a phenomenological…

Superconductivity · Physics 2009-11-10 Yasuhiro Asano , Yukio Tanaka , Satoshi Kashiwaya

We investigated the effect due to perpendicular magnetic field on quantum wires where spin-orbit interaction (SOI) of electrons is not neglected. Based on the calculated energy dispersion, the nonlinear ballistic conductance ($G$) and…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Godfrey Gumbs , Antonios Balassis , Danhong Huang , Sheehan Ahmed , Ryan Brennan

Spin-polarized transport is investigated in normal metal-superconductor (NS) junctions as a function of interface transmissivity as well as temperature when the density of states of a superconductor is Zeeman-split in response to an…

Mesoscale and Nanoscale Physics · Physics 2008-04-03 F. Giazotto , F. Taddei

A ballistic strip of graphene (width W>> length L) connecting two normal metal contacts is known to have a minimum conductivity of 4e^{2}/pi h at the Dirac point of charge neutrality. We calculate what happens if one of the two contacts…

Mesoscale and Nanoscale Physics · Physics 2013-07-09 A. R. Akhmerov , C. W. J. Beenakker

We construct a semi-microscopic theory, to describe the optical conductivity of GaMnAs in the dilute limit, x = 1%. We construct an effective Hamiltonian that captures inside-impurity band optical transitions as well as transitions between…

Materials Science · Physics 2010-06-22 C. P. Moca , G. Zarand , M. Berciu

We calculate the tunneling conductance of a graphene normal metal-insulator-superconductor (NIS) junction with a barrier of thickness $d$ and with an arbitrary voltage $V_0$ applied across the barrier region. We demonstrate that the…

Mesoscale and Nanoscale Physics · Physics 2018-08-29 Subhro Bhattacharjee , Moitri Maiti , K. Sengupta

We present a formula for tunneling conductance in ballistic ferromagnet/ferromagnetic insulator/superconductor junctions where the superconducting state has opposite spin pairing symmetry. The formula can involve correctly a ferromagnetism…

Superconductivity · Physics 2015-03-20 Nobukatsu Yoshida , Masashi Yamashiro

The conductance quantization and shot noise below the first conductance plateau $G_0 = 2e^2/h$ are measured in a quantum point contact fabricated in a GaAs/AlGaAs tunnel-coupled double quantum well. From the conductance measurement, we…

Mesoscale and Nanoscale Physics · Physics 2020-03-25 D. Terasawa , S. Norimoto , T. Arakawa , M. Ferrier , A. Fukuda , K. Kobayashi , Y. Hirayama

We formulate and apply a low-energy transport theory for hybrid quantum devices containing junctions of topological superconductor (TS) wires and conventional normal (N) or superconducting (S) leads. We model TS wires as spinless $p$-wave…

Superconductivity · Physics 2016-07-04 A. Zazunov , R. Egger , A. Levy Yeyati

We apply the scattering matrix approach to the triplet proximity effect in superconductor-half metal structures. We find that for junctions that do not mix different orbital modes, the zero bias Andreev conductance vanishes, while the zero…

Superconductivity · Physics 2009-01-27 B. Béri , J. N. Kupferschmidt , C. W. J. Beenakker , P. W. Brouwer

We present a first-principles investigation to show that the contact conductance of a half conductance quantum ($G_0/2$) found previously does not generally hold for single-atom magnetic junctions composed of a tip and an adatom dsorbed on…

Mesoscale and Nanoscale Physics · Physics 2013-06-17 Yi-qun Xie , Qiang Li , Lei Huang , Xiang Ye , San-Huang Ke