Geometrical confinement effects in layered mesoscopic vortex-matter

TL;DR

This study investigates how the geometry of mesoscopic samples influences vortex arrangements in layered superconductors, revealing that confinement shapes defect densities and vortex alignment, with implications for understanding vortex matter.

Contribution

It provides experimental and simulation evidence that geometrical confinement determines defect density and vortex alignment in mesoscopic vortex matter, highlighting the role of sample shape.

Findings

Circular edges have higher defect densities than square edges.

Vortex alignment with sample edges depends on geometry.

Defect density is governed by confinement, not out-of-equilibrium effects.

Abstract

We study geometrical confinement effects in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8 +\delta}$ mesoscopic vortex-matter with edge-to-surface ratio of $7-12$%. Samples have in-plane square and circular edges, 30\,$\mu$m widths, and $\sim 2\,\mu$m thickness. Direct vortex imaging reveals the compact planes of the structure align with the sample edge by introducing topological defects. The defects density is larger for circular than for square edges. Molecular dynamics simulations suggest this density is not an out-of-equilibrium property but rather determined by the geometrical confinement.