Absence of charge backscattering in the nonequilibrium current of normal-superconductor structures

Abstract

We study the nonequilibrium transport properties of a normal-superconductor-normal structure, focussing on the effect of adding an impurity in the superconducting region. Current conservation requires the superfluid velocity to be nonzero, causing a distortion of the quasiparticle dispersion relation within the superconductor. For weakly reflecting interfaces we find a regime of intermediate voltages in which Andreev transmission is the only permitted mechanism for quasiparticles to enter the superconductor. Impurities in the superconductor can only cause Andreev reflection of these quasiparticles and thus cannot degrade the current. At higher voltages, a state of gapless superconductivity develops which is sensitive to the presence of impurities.

Latex file, 11 pages, 2 figures available upon request [email protected], to be published in Journal of Physics: Condensed Matter

References in corpus (3)

• Crossover from the Josephson effect to bulk superconducting flow
• Self-consistent current-voltage characteristics of superconducting nano-structures
• SELFCONSISTENT CURRENT-VOLTAGE CHARACTERISTICS OF NORMAL-SUPERCONDUCTOR INTERFACES

Cited by in corpus (3)

• Self-consistent scattering description of transport in normal-superconductor structures
• Quasiclassical theory of charge transport across mesoscopic normal metal-superconducting heterostructures with current conservation
• Transport in normal-superconductor-normal structures with local conservation of current