Causes and consequences of ordering and dynamic phases of confined vortex rows in superconducting nanostripes

TL;DR

This paper investigates how nanoscale confinement affects vortex arrangements and dynamics in superconducting nanostripes, revealing phase diagrams and transitions that influence superconducting electronic properties.

Contribution

It provides a detailed phase diagram of vortex configurations in superconducting nanostripes and analyzes vortex dynamics under electrical current, highlighting the effects of confinement.

Findings

Confinement organizes vortices into distinct configurations.

Vortex density is reduced due to confinement effects.

Transitions between asynchronous and synchronous vortex rows occur with current variation.

Abstract

Understanding the behaviour of vortices under nanoscale confinement in superconducting circuits is of importance for development of superconducting electronics and quantum technologies. Using numerical simulations based on the Ginzburg-Landau theory for non-homogeneous superconductivity in the presence of magnetic fields, we detail how lateral confinement organises vortices in a long superconducting nanostripe, and present a phase diagram of vortex configurations as a function of the stripe width and magnetic field. We discuss why average vortex density is reduced and reveal that confinement also has profound influence on vortex dynamics in the dissipative regime under sourced electrical current, mapping out transitions between asynchronous and synchronous vortex rows crossing the nanostripe as the current is varied. Synchronous crossings are of particular interest, since they cause single-mode modulations in the voltage drop along the stripe in a high (typically GHz-to-THz) frequency range.