Adherence of the rotating vortex lattice in the noncentrosymmetric superconductor Ru$_{7}$B$_{3}$ to the London model

TL;DR

This study investigates the vortex lattice behavior in the noncentrosymmetric superconductor Ru$_7$B$_3$, showing it conforms to the anisotropic London model despite unusual vortex arrangements.

Contribution

It provides experimental validation that the vortex lattice in Ru$_7$B$_3$ adheres to the London model, confirming theoretical predictions about effects of broken inversion symmetry.

Findings

Vortex lattice form factor matches anisotropic London model

Penetration depth and coherence length values are extracted

Vortex arrangements show complex field-history dependence

Abstract

The noncentrosymmetric superconductor Ru$_7$B$_3$ has in previous studies demonstrated remarkably unusual behaviour in its vortex lattice, where the nearest neighbour directions of the vortices dissociate from the crystal lattice and instead show a complex field-history dependence, and the vortex lattice rotates as the field is changed. In this study, we look at the vortex lattice form factor of Ru$_7$B$_3$ during this field-history dependence, to check for deviations from established models, such as the London model. We find that the data is well described by the anisotropic London model, which is in accordance with theoretical predictions that the alterations to the structure of the vortices due to broken inversion symmetry should be small. From this, we also extract values for the penetration depth and coherence length.