Co-existence of the Meissner and vortex-state on a superconducting spherical shell

TL;DR

This paper investigates how superconducting spherical shells can simultaneously host Meissner and vortex states, revealing unique vortex behaviors influenced by geometry and magnetic fields, with implications for nanoscale superconducting devices.

Contribution

It demonstrates the coexistence of Meissner and vortex states on spherical shells and explains vortex dynamics driven by geometry and magnetic forces, a novel insight in superconductivity.

Findings

Vortex patterns are driven to the poles by the Magnus-Lorentz force.

A Meissner belt forms around the sphere's equator.

Paramagnetic vortex states can be stable in small, thin shells.

Abstract

We show that on superconducting spherical nanoshells, the co-existence of the Meissner state with a variety of vortex patterns drives the phase transition to higher magnetic fields. The spherical geometry leads to a Magnus-Lorentz force pushing the nucleating vortices and antivortices towards the poles, overcoming local pinning centers, preventing vortex-antivortex recombination and leading to the appearance of a Meissner belt around the sphere's equator. In sufficiently small and thin spherical shells paramagnetic vortex states can be stable, enabling spatial separation of freely moving shells with different radii and vorticity in an inhomogeneous external magnetic field.