# Dynamics of DC-SQUID with nontrivial barriers under external radiation

## TL;DR

This paper investigates the phase dynamics and IV characteristics of DC-SQUIDs with topologically nontrivial barriers, revealing unique behaviors in Shapiro steps, resonance effects, and chaos reduction under external radiation.

## Contribution

It introduces the analysis of nontrivial barrier effects in DC-SQUIDs, highlighting differences in Shapiro step widths and resonance phenomena compared to trivial barriers.

## Key findings

- Nontrivial barriers increase the width of even Shapiro steps.
- Resonance branches decrease maximum Shapiro step width and amplitude dependence periods.
- Resonance reduces chaotic behavior in IV curves.

## Abstract

We study the phase dynamics and IV--characteristics of DC--SQUIDs consisting of Josephson junctions with topologically nontrivial barriers, which cause the appearance of Majorana bound state. Its comparative analysis with the trivial case is performed. The influence of external electromagnetic radiation is considered and the analysis of the amplitude dependence of the Shapiro step widths is performed. We have shown that in nontrivial case the width of even harmonic of Shapiro step is larger than width of odd harmonic. In the presence of external dc magnetic field a beating state is realized in the DC--SQUID, which leads to a resonance branch in the IV--curve. We show that in the presence of resonance branch the maximum width of Shapiro step and periods of its amplitude dependence are decreased in comparison of situation without resonance in both trivial and nontrivial cases. We demonstrate that in the presence of the resonance branch the chaotic behavior of IV--curve is reduced.