Vortex structure in a $d$-wave superconductor obtained by a confinement transition from the pseudogap metal

TL;DR

This paper models the vortex structure in a d-wave superconductor emerging from a pseudogap metal using a continuum gauge theory, revealing unique electronic features consistent with experimental STM observations.

Contribution

It introduces a continuum Higgs condensation theory for vortices in a d-wave superconductor derived from a pseudogap metal, highlighting novel electronic density of states features.

Findings

No zero-bias peak in local density of states

Presence of sub-gap peaks with anti-phase modulations

Charge order near vortex core

Abstract

We compute the structure of flux $h/(2e)$ vortices in a d-wave superconductor which emerges from a higher temperature pseudogap metal. Such a transition is described by a continuum theory of the Higgs condensation of 2 flavors of charge $e$ bosons which are fundamentals of an emergent SU(2) gauge field. Period-2 charge order is present near the vortex center. Upon coupling the electrons to the superconducting and charge order parameters, we find that the electronic local density of states does not have a zero-bias peak, in contrast to BCS theory. But there are sub-gap peaks at positive and negative bias, and these exhibit anti-phase periodic spatial modulations, similar to observations in scanning tunneling microscopy experiments in the underdoped cuprates (K. Matsuba et al., J. Phys. Soc. Jpn. 76, 063704 (2007)).