Experimental observation of the longitudinal plasma excitation in intrinsic Josephson junctions

TL;DR

This paper reports the experimental detection of longitudinal plasma waves in intrinsic Josephson junctions, confirming theoretical predictions and revealing temperature-dependent behavior of plasma wave excitation.

Contribution

It provides the first experimental observation of the breakpoint region associated with plasma wave excitation in IJJs, validating theoretical models.

Findings

Breakpoint region observed in IVCs at 4.2 K

Temperature dependence matches theoretical predictions

Wave number of plasma wave varies with temperature

Abstract

We have investigated the current-voltage characteristics (IVCs) of intrinsic Josephson junctions (IJJs). Recently, it is predicted that the longitudinal plasma wave can be excited by the parametric resonance in IJJs. Such an excitation induces a singularity called as breakpoint region around switch back region in the IVC. We have succeeded in the observation of the breakpoint region in the IVC of the mesa with 5 IJJs at 4.2 K. Furthermore, it is found that the temperature dependence of the breakpoint current is in agreement with the theoretical prediction. This suggests that the wave number of the excited plasma wave varies with temperature.