Possible Dynamic States in Inductively Coupled Intrinsic Josephson Junctions of Layered High-$T_c$ Superconductors

TL;DR

This paper reports a newly identified dynamic state in inductively coupled intrinsic Josephson junctions, characterized by uniform plasma oscillations along the c axis and periodic phase kinks, explaining recent terahertz radiation experiments.

Contribution

It introduces a novel dynamic state in Josephson junctions with specific plasma oscillation and phase kink features, supported by simulations and theoretical analysis.

Findings

Discovery of a new dynamic state with uniform plasma oscillation along the c axis.

Manifestation of this state as current steps at all cavity modes in IV characteristics.

Generation of harmonics in frequency spectra during the state.

Abstract

Based on computer simulations and theoretical analysis, a new dynamic state is found in inductively coupled intrinsic Josephson junctions in the absence of an external magnetic field. In this state, the plasma oscillation is uniform along the c axis and there are $(2m+1)\pi$ phase kinks, with $m$ being an integer, periodic and thus non-uniform in the $c$ direction. In the IV characteristics, the state manifests itself as current steps occurring at all cavity modes. Inside the current steps, the plasma oscillation becomes strong, which generates several harmonics in frequency spectra at a given voltage. The recent experiments on terahertz radiations from the mesa of a BSCCO single crystal can be explained in terms of this state.