Staggered flux vortices and the superconducting transition in the layered cuprates

TL;DR

This paper introduces a model for high-temperature cuprate superconductors where staggered flux vortices unbind at the transition, explaining the pseudogap phase and large Nernst signals observed above T_c.

Contribution

It proposes that staggered flux vortices, rather than conventional vortices, drive the superconducting transition in layered cuprates, based on an SU(2) gauge theory approach.

Findings

Staggered flux vortices are energetically favored over conventional vortices.

The model explains a phase with mobile vortices above T_c with normal transport properties.

Large Nernst signals are consistent with the presence of staggered flux vortices.

Abstract

We propose an effective model for the superconducting transition in the high-T_c cuprates motivated by the SU(2) gauge theory approach. In addition to variations of the superconducting phase we allow for local admixture of staggered flux order. This leads to an unbinding transition of vortices with staggered flux core that are energetically preferable to conventional vortices. Based on parameter estimates for the two-dimensional t-J model we argue that the staggered flux vortices provide a way to understand a phase with a moderate density of mobile vortices over a large temperature range above T_c that yet exhibits otherwise normal transport properties. This picture is consistent with the large Nernst signal observed in this region.