J. Faundez | Searcharxiv

arXiv2025

Superconducting diode effect in a meso-wedge geometry with Abrikosov vortices

In this study, we explore the behavior of a superconducting meso-wedge geometry in 3+1 dimensions (three spatial dimensions plus time) subjected to external transport currents at its boundaries and surfaces, as well as external fields applied along the $\hat{z}$-direction. The transport currents are included as two opposite polarities, $\textbf{J}>0$ and $\textbf{J}<0$. Using the generalized time-dependent Ginzburg-Landau theory and considering the order parameter $κ$, we focus on two scenarios: a fixed external magnetic field with variable $κ$, and fixed $κ$ with variable external magnetic field. As a result, under both scenarios, we analyze the voltage-current characteristics of the superconducting meso-wedge, finding that the critical currents differ between polarities, demonstrating the system's non-reciprocity. We further examine the efficiency of the diode as a function of $κ$ and the external magnetic field applied. Furthermore, our observations reveal that the current polarity strongly influences the vortex configuration, the parameter $κ$, and the applied magnetic field. In particular, the formation of Abrikosov-type vortices exhibits pronounced inhomogeneity depending on the direction of the transport currents. This underscores that the diode effect in the superconducting meso-wedge is intimately associated with the anisotropic nucleation of Abrikosov vortices. Notably, the emergence of polarity-dependent vortex patterns can serve as a distinctive hallmark of the diode effect in these superconducting systems.

cond-mat.supr-con↗

arXiv2024

Evidence of controlling vortex matter via a superconducting Nanobridge

We theoretically investigate the magnetic response on a three-dimensional superconducting nanobridge system, which is compound of two parallel parallelepiped (samples) connected through a nanobridge of size $\mathbf{L}$ and thickness $\mathbf{x}$, which mediates interactions between them. This study is conducted in the presence of a magnetic field $\mathbf{H}$ and the transport of a direct current $\mathbf{J}$. We use the well-know time dependent Ginzburg-Landau theory ($\mathbf{TDGL}$) for analyzed the possible effects on the density Gibbs free energy $\mathbf{F}$, magnetization $\mathbf{M}$, and superconducting electronic Cooper pair density $|ψ|^{2}$. We are interested in studying two cases: varying the $\mathbf{L}$ and $\mathbf{x}$ of the nanobridge in the absence of induced $\mathbf{J}$, and including the induction of external $\mathbf{J}$ for fixed $\mathbf{L}$ and $\mathbf{x}$. We find that $\mathbf{L}$ and $\mathbf{x}$ play an essential role in stabilizing (controlling) vortex states in the nanobridge, and the presence of induced $\mathbf{J}$ ($\mathbf{J}>0$ and $\mathbf{J}<0$), with a fixed $\mathbf{L}$ and $\mathbf{x}$, causes the movement of vortex states in the nanobridge just when $\mathbf{J}$ is induced at both faces of superconducting nanobridge system.

cond-mat.supr-con↗