Possible vortex splitting in the cuprate superconductors

TL;DR

This paper suggests that vortex splitting in cuprate superconductors into fractional vortices may be static, driven by pairing interactions, with a model showing how these partons are confined or deconfined depending on system parameters.

Contribution

It introduces a static interpretation of vortex splitting in cuprates and models the conditions under which fractional vortices are confined or deconfined.

Findings

Vortices can split into two half-flux vortices (partons).

Partons are confined by a string with phase jumps of pi.

Deconfinement occurs at a critical pairing energy difference.

Abstract

We propose that the observed splitting of the vortices in the cuprates into fractional vortices (partons) may be of static rather than of dynamic origin. This interpretation is backed by a study of a model with a dominant d-wave and subdominant s-wave pairing interaction. We find that the vortex may split into two partons, both of which carry one half of the magnetic flux quantum. The partons are hold together by a confining string along which the phase jumps approximately by pi and their equilibrium distance increases with lowering the energy difference epsilon between the pairing states. The partons become deconfined at the critical point where epsilon vanishes.