Dynamics of a suspended nanowire driven by an ac Josephson current in an inhomogeneous magnetic field

TL;DR

This paper investigates how a suspended nanowire in a Josephson junction responds dynamically to an ac Josephson current within an inhomogeneous magnetic field, revealing complex motion regimes including chaos.

Contribution

It introduces a detailed analysis of nonlinear nanowire dynamics driven by Josephson currents in inhomogeneous magnetic fields, combining analytical and numerical methods.

Findings

Resonance induces whirling nanowire motion.

Different magnetic inhomogeneity levels lead to various dynamic regimes.

Transitions between static, periodic, and chaotic motion are characterized.

Abstract

We consider a voltage-biased nanoelectromechanical Josephson junction, where a suspended nanowire forms a superconducting weak-link, in an inhomogeneous magnetic field. We show that a nonlinear coupling between the Josephson current and the magnetic field generates a Laplace force that induces a whirling motion of the nanowire. By performing an analytical and a numerical analysis, we demonstrate that at resonance, the amplitude-phase dynamics of the whirling movement present different regimes depending on the degree of inhomogeneity of the magnetic field: time independent, periodic and chaotic. Transitions between these regimes are also discussed.