Orientational coupling between the vortex lattice and the crystalline lattice in a weakly pinned Co0.0075NbSe2 single crystal

TL;DR

This study provides experimental evidence of strong orientational coupling between the vortex lattice and the crystalline lattice in a weakly pinned Co-doped NbSe2 crystal, revealing how magnetic field influences vortex lattice stability and order.

Contribution

It demonstrates the direct imaging of vortex-crystal lattice coupling and its enhancement with increasing magnetic field in a specific superconductor.

Findings

Vortex lattice aligns with the crystal lattice at low fields.

Coupling strength increases with magnetic field.

Vortex orientational order persists despite topological disorder.

Abstract

We report experimental evidence of strong orientational coupling between the crystal lattice and the vortex lattice in a weakly pinned Co-doped NbSe2 single crystal through direct imaging using low temperature scanning tunneling microscopy/spectroscopy. At low fields, when the magnetic field is applied along the six-fold symmetric c-axis of the NbSe2 crystal, the equilibrium configuration of the vortex lattice is preferentially aligned along the basis vectors of the crystal lattice. The orientational coupling between the vortex lattice and crystal lattice becomes more pronounced as the magnetic field is increased. We show that this coupling enhances the stability of the orientational order of the vortex lattice, which persists even in the disordered state at high fields where dislocations and disclinations have destroyed the topological order.