Negative differential resistance in Josephson junctions coupled to a cavity

TL;DR

This paper investigates how negative differential resistance regions in Josephson junctions, influenced by cavity coupling, affect their dynamics and THz radiation emission, revealing complex interactions relevant for experimental interpretation.

Contribution

It provides a detailed analysis of the dynamics of Josephson junctions with negative differential resistance influenced by cavity coupling, highlighting complex interactions not previously well understood.

Findings

Negative differential resistance regions can be induced by cavity coupling.

Complex and unexpected interactions occur in the junction dynamics.

Insights may improve interpretation of THz radiation experiments.

Abstract

Regions with negative differential resistance can arise in the IV curve of Josephson junctions and this phenomenon plays an essential role for applications, in particular for THz radiation emission. For the measurement of high frequency radiation from Josephson junctions, a cavity - either internal or external - is often used. A cavity may also induce a negative differential resistance region at the lower side of the resonance frequency. We investigate the dynamics of Josephson junctions with a negative differential resistance in the quasi particle tunnel current, i.e. in the McCumber curve. We find that very complicated and unexpected interactions take place. This may be useful for the interpretation of experimental measurements of THz radiation from intrinsic Josephson junctions.