Quantum levels and quasi-local states of <i>SINIS</i> structures

Gogadze, G. A.; Kosevich, A. M.

doi:10.1063/1.593633

Cited by 14 publications

(7 citation statements)

References 19 publications

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“…Coherent effects in the SINIS junctions were also considered theoretically. 9,10,16,17 In spite of this work, the excitation spectrum and phasecoherent transport in such junctions deserves further study. Furthermore, SINIS junctions represent a rich physical system, and are potentially useful for many applications.…”

Section: Introductionmentioning

confidence: 93%

Manifestation of coherent effects in the conductivity of superconductor/insulator/normal-metal/insulator/superconductor junctions

2003

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An experimental and theoretical study is presented of coherent effects in electron transport in the doublebarrier SINIS junctions ͑where S, I, and N denote a superconductor, insulator, and normal metal, respectively͒. The appearance of a steplike subgap structure in the current-voltage characteristics of the Nb/Al/AlO x /Al/AlO x /Al/Nb superconducting junctions at a voltage Vϳ⌬ Nb /e ͑where ⌬ Nb is the superconducting energy gap of Nb͒ is interpreted as a manifestation of a nonequilibrium supercurrent at finite dc bias voltage ͑Finite-Bias Josephson Effect͒. The origin of this effect lies in the energy-band structure associated with a set of macroscopic quantum states characteristic of a SINIS junction. Specifically, the junction can have an energy level near energy ⌬ Nb , which provides an additional channel for dc Josephson current at V ϳ⌬ Nb /e. In addition, sharp features in the conductivity at a voltage near the gap-sum voltage were observed in both SINIS and SINININIS junctions, implying correlated quasiparticle tunneling in multiple-barrier junctions. Our theoretical model provides a good qualitative description of the quasiparticle conductivity, including narrow peaks at finite voltage and a zero-voltage anomaly observed on some samples, and suggests an alternative explanation of a feature interpreted earlier as gap-difference feature associated with the tunneling extraction of quasiparticles from the middle Al layer.

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Section: Introductionmentioning

confidence: 93%

Manifestation of coherent effects in the conductivity of superconductor/insulator/normal-metal/insulator/superconductor junctions

2003

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“…The effect of interface scattering on the continuum part of the spectrum has been analyzed in Ref. 25.…”

Section: Quasiparticle Spectrummentioning

confidence: 99%

“…After evaluating the normal scattering amplitudes we can reinstall the superconductors and match the scattering states in the normal region with the evanescent modes in the superconducting banks. We make use of the Andreev approximation 22 and obtain the quantization condition 11,13,23 cos…”

Section: B Sinis-junctionsmentioning

confidence: 99%

Supercurrents through gated superconductor–normal-metal–superconductor contacts: The Josephson transistor

et al. 2001

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We analyze the transport through a narrow ballistic superconductor-normal-metal-superconductor Josephson contact with nonideal transmission at the superconductor-normal-metal interfaces, e.g., due to insulating layers, effective mass steps, or band misfits ͑SIN interfaces͒. The electronic spectrum in the normal wire is determined through the combination of Andreev reflection and normal reflection at the SIN interfaces. Strong normal scattering at the SIN interfaces introduces electron-and holelike resonances in the normal region that show up in the quasiparticle spectrum. These resonances have strong implications for the critical supercurrent I c that we find to be determined by the lowest quasiparticle level: tuning the potential x0 to the points where electron-and holelike resonances cross, we find sharp peaks in I c , resulting in a transistor effect. We compare the performance of this resonant Josephson-transistor with that of a superconducting single electron transistor.

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“…Hence such processes in these materials may be significant in the calculations of quantum effects. In a recent publication [8], we derived a general dispersion equation describing the spectrum of quasiparticles in a SINIS structure taking into account the Andreev scattering as well as the normal scattering of quasiparticles at the interfaces between the media. In order to calculate the current, we must calculate the spectrum of quasiparticles in a point contact containing an insulating barrier.…”

Section: Introductionmentioning

confidence: 99%

Dc Josephson Current for a Superconducting Point Contact With a Tunneling Barrier

Gogadze

2000

Magnetic and Superconducting Materials

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The microscopic theory of dc Josephson effect for a short clean superconducting point contact with a tunnel barrier is developed. The influence of the ordinary quasiparticle scattering on the off-diagonal potential A of the superconductor is studied. It is shown that such processes may be significant in high-7r superconductors for the case of a barrier with high transmittance. The current-phase relation for a point contact at arbitrary temperatures is calculated.

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Quantum levels and quasi-local states of SINIS structures

Cited by 14 publications

References 19 publications

Manifestation of coherent effects in the conductivity of superconductor/insulator/normal-metal/insulator/superconductor junctions

Manifestation of coherent effects in the conductivity of superconductor/insulator/normal-metal/insulator/superconductor junctions

Supercurrents through gated superconductor–normal-metal–superconductor contacts: The Josephson transistor

Dc Josephson Current for a Superconducting Point Contact With a Tunneling Barrier

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