Stick-slip Phenomena and Memory Effects in Moving Vortex Matter

TL;DR

This study uses advanced scanning tunneling spectroscopy to observe and control vortex core trajectories in a superconductor, revealing complex stick-slip dynamics, memory effects, and connecting vortex behavior with theoretical models.

Contribution

It provides the first direct experimental observation of vortex trajectories with high resolution and links these findings to theoretical models of vortex pinning and memory effects.

Findings

Captured vortex depinning threshold in a superconductor.

Identified stick-slip motion mimicking lattice periodicity.

Linked vortex dynamics to memory effects and theoretical models.

Abstract

Manipulating vortices in non-conventional superconductors is nowadays a challenging path toward controlling functionalities for superconducting nanodevices. Here, we directly observe and control single vortex core trajectories with unmatched resolution using a new scanning tunneling spectroscopy at very low temperature. Our data show the depinning threshold of a Bragg-glass in a weakly disordered superconductor, a clean 2H-NbSe2 crystal. We first experimentally capture the linear and collective response, the Campbell regime. Upon strong drives, the oscillating trajectories perform a series of stick-slip motions that mimics the lattice periodicity. We then theoretically elucidate this peculiar non-linear regime by solving the Langevin dynamics equations. We additionally explore the impact of initial conditions and reveal an enhancement of the long-range correlations with the cooling procedure. Finally, our work establishes a connection between theory of vortex pinning, memory effects and vortex lineshapes, thus offering a new platform to investigate the relationship between viscous media and individual controllable objects in any many-body systems.