Peculiarities of the stacks with finite number of intrinsic Josephson junctions

TL;DR

This paper investigates how the number and boundary conditions of intrinsic Josephson junction stacks affect their current-voltage characteristics, revealing the role of parametric resonance and plasma waves in the breakpoint region.

Contribution

It provides new insights into the influence of junction number and boundary conditions on the breakpoint behavior in Josephson stacks, with a proposed diagnostic method.

Findings

Breakpoint region absent for even junction stacks with periodic boundaries.

Breakpoint current increases with junction number for odd and nonperiodic boundary stacks.

Saturation of breakpoint current depends on junction coupling and boundary conditions.

Abstract

We study the breakpoint region on the outermost branch of current-voltage characteristics of the stacks with different number of intrinsic Josephson junctions. We show that at periodic boundary conditions the breakpoint region is absent for stacks with even number of junctions. For stacks with odd number of junctions and for stacks with nonperiodic boundary conditions the breakpoint current is increased with number of junctions and saturated at the value corresponding to the periodic boundary conditions. The region of saturation and the saturated value depend on the coupling between junctions. We explain the results by the parametric resonance at the breakpoint and excitation of the longitudinal plasma wave by the Josephson oscillations. A way for the diagnostics of the junctions in the stack is proposed.