Coupling of intrinsic Josephson oscillations in layered superconductors by charge fluctuations

TL;DR

This paper investigates how charge fluctuations couple Josephson oscillations in layered superconductors, deriving a general current density formula and analyzing the impact on system dynamics and experimental current-voltage characteristics.

Contribution

It introduces a formalism for coupling Josephson oscillations via charge fluctuations and explores their effects on non-linear dynamics and experimental observations.

Findings

Charge fluctuations induce coupling between Josephson junctions.

Coupling influences the current-voltage characteristics.

Upper limits for coupling strength are estimated from experiments.

Abstract

The coupling of Josephson oscillations in layered superconductors is studied with help of a tunneling Hamiltonian formalism. The general form of the current density across the barriers between the superconducting layers is derived. The induced charge fluctuations on the superconducting layers lead to a coupling of the Josephson oscillations in different junctions. A simplified set of equations is then used to study the non-linear dynamics of the system. In particular the influence of the coupling on the current-voltage characteristics is investigated and upper limits for the coupling strength are estimated from a comparison with experiments on cuprate superconductors.