Anisotropic vortex motion and two-dimensional superconducting transition

TL;DR

This paper investigates how anisotropic pinning affects vortex motion and resistance in two-dimensional superconductors, revealing multiple critical temperatures and fields along different directions, which advances understanding of the BKT and $H_{c2}$ transitions.

Contribution

It introduces an anisotropic pinning potential to study vortex behavior, showing directional dependence of critical temperatures and fields in 2D superconductors.

Findings

Anisotropic pinning leads to distinct critical temperatures along different directions.

Multiple critical fields are observed due to anisotropic effects.

The results suggest a route to realize multiple critical points in 2D superconductors.

Abstract

Vortex motion plays a central role in determining the resistance of two-dimensional superconductors, both in the context of the Berezinskii-Kosterlitz-Thouless (BKT) transition and in the mixed state of type-II superconductors under magnetic fields. In this study, we introduce an anisotropic pinning potential to investigate vortex-induced resistance across the BKT transition and the upper critical field $H_{c2}$ transition. Our results demonstrate that the anisotropic pinning potential gives rise to distinct critical temperatures and upper critical fields along two orthogonal directions of current transport. These findings provide a general route toward the realization of multiple "critical temperatures" in two-dimensional superconductors.