Dynamical regimes of ultrafast kinematic vortices in the resistive state of mesoscopic superconductors

TL;DR

This study investigates the ultrafast dynamics of kinematic vortices in mesoscopic superconductors under external magnetic fields and currents, revealing distinct behaviors and phase boundaries crucial for fluxonics control.

Contribution

It provides a detailed phase diagram of kV dynamics influenced by magnetic fields and currents, highlighting three regimes and the impact of surface barriers on vortex velocities.

Findings

Vortex behavior varies with magnetic field strength.

A phase diagram delineates three vortex regimes.

Surface barriers influence vortex velocities at specific fields.

Abstract

A superconducting state coexists with static electrical fields under the formation of phase-slips and kinematic vortices (kV 's). Besides that, such a resistive state installed in the superconductor is not desirable in many applications. Then, it is essential to know the ultrafast kV dynamics for controlling the fluxonics of the system. Thus, in this work, we studied the dynamics of the kV 's in a mesoscopic superconductor under the influence of external magnetic fields (H) and transport currents (Jtr). As a result, the kV dynamics are affected by increasing H. With those significant changes, it was possible to build a Jtr(H) phase diagram. There, in between the Meissner and the normal states, the kV 's present three distinct behaviors. For high fields, the vortices behave as Abrikosov-like ones, with velocities two orders of magnitude lower than those at low fields regime. Besides that, one demonstrates how the interplay between Jtr and the shielding currents, its controlled by H, allowing for some quantitative predictions of boundaries in the phase diagram. Additionally, for H's where only a kV is nucleated, for tenths of picoseconds, a surface barrier effect acts over the instantaneous velocity of the kV.