Edge critical currents of dense Josephson vortex lattice in layered superconductors

TL;DR

This paper calculates how the critical current in dense Josephson vortex lattices in layered superconductors depends on magnetic field, revealing boundary effects, oscillatory behavior, and a unique 1/B dependence with flux quantum oscillations.

Contribution

It provides a detailed theoretical analysis of boundary-induced deformations and oscillations in the critical current of dense Josephson vortex lattices under high magnetic fields.

Findings

Critical current exhibits a 1/B dependence with strong oscillations.

Oscillation period corresponds to adding one flux quantum per two junctions.

Boundary interactions cause flux-flow voltage oscillations consistent with experiments.

Abstract

We calculate the field dependence of the critical current for the dense Josephson vortex lattice which is created by large magnetic field $B$ applied along the layers of atomically layered superconductors. In clean samples a finite critical current appears due to the interaction of the lattice with the boundaries. The boundary induces an alternating deformation of the lattice decaying inside the sample at the typical length, which is larger than the Josephson length and increases proportional to the magnetic field. The exact shape of this deformation and the total current flowing along the surface are uniquely determined by the position of the lattice in the bulk. The total maximum Josephson current has overall 1/B dependence with strong oscillations. In contrast to the well-known Fraunhofer dependence, the period of oscillations corresponds to adding \emph{one flux quantum per two junctions}. Due to interaction with the boundaries, the flux-flow voltage for slow lattice motion also oscillates with field, in agreement with recent experiments.