Current-phase relation in an intermediately coupled superconductor-superconductor junction

D. Agassi; J. R. Cullen

doi:10.1103/PhysRevB.54.10112

← Back to search

Current-phase relation in an intermediately coupled superconductor-superconductor junction

D. Agassi, J. R. Cullen

DOI 10.1103/PhysRevB.54.10112 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

The limiting configuration of the S-N-S′ junction in which the N-layer thickness is of the order of the screening length in metals (≊1–2 Å) may serve as a model for a clean S-S′ interface. This configuration supports one N-layer-attached gap state (manifold), with eigenenergy close to and less than the smaller superconducting gap. This gap state is interpreted as the excitation associated with breakage of interface-attached Cooper pairs, comprised of one electron from each side of the thin-N layer. The corresponding junction’s current-phase (ψ) relation is calculated. The gap state is shown to contribute an appreciable ‘‘sin(2ψ)’’ correction term to the ‘‘sin(ψ)’’ Josephson term. The corresponding maximum-current magnetic-flux dependence of a two-junction configuration (SQUID) is predicted to have zeros shifted from their common loci at half-integer flux quanta.