Impact of the transport supercurrent on the Josephson effect

TL;DR

This paper investigates how an externally injected transport supercurrent influences the Josephson effect in weak links between superconductors, revealing conditions where quasiparticles induce boundary currents opposite to the supercurrent.

Contribution

It introduces models for weak links with transport supercurrent effects, deriving low-temperature current-phase relations and analyzing quasiparticle boundary currents.

Findings

Quasiparticles can generate boundary currents opposite to the supercurrent.

The current-phase relations depend on the phase difference and superfluid velocity.

Different behaviors are shown for conventional and d-wave superconductor interfaces.

Abstract

We study the weak link between current-carrying superconductors, both conventional and d-wave. The state of the system is controlled by two parameters: the order parameter phase difference $\phi$ and the superfluid velocity $v_{s}$, which parameterizes the parallel to the boundary transport supercurrent which is injected externally. The low-temperature current-phase relations are derived. We consider two models of weak links: a constriction between two conventional superconductors and a plane boundary between two differently orientated d-wave superconductors. We show that for some relation between $\phi $ and $v_{s}$ quasiparticles create the current along the boundary which flows in the direction opposite to the transport supercurrent.