Shunt-capacitor-assisted synchronization of oscillations in intrinsic Josephson junctions stack

TL;DR

This paper demonstrates that a shunt capacitor can stabilize and enhance synchronized oscillations in intrinsic Josephson junction stacks, especially in small crystals, by providing an alternative coupling mechanism to radiative effects.

Contribution

It introduces shunt capacitance as a new method to synchronize Josephson junctions, independent of geometry, and explores its effects on oscillation stability and radiation power.

Findings

Shunt capacitor stabilizes synchronized oscillations.

Synchronization is effective even in small junction stacks.

Shunt tuning affects radiation power output.

Abstract

We show that shunt capacitor stabilizes synchronized oscillations in intrinsic Josephson junction stacks biased by DC current. This synchronization mechanism has an effect similar to the previously discussed radiative coupling between junctions, however, it is not defined by the geometry of the stack. It is particularly important in crystals with smaller number of junctions, where radiation coupling is week, and is comparable with the effect of strong super-radiation in crystal with many junctions. The shunt also helps to enter the phase-locked regime in the beginning of oscillations, after switching on the bias current. Shunt may be used to tune radiation power, which drops as shunt capacitance increases.