Electronic structure of topological defects in the pair density wave superconductor

TL;DR

This paper investigates the electronic structure of topological defects in pair density wave superconductors, focusing on half-vortices and their experimental signatures in STM, revealing unique spectral and symmetry-breaking features.

Contribution

It provides a detailed analysis of the electronic topological defects in PDW superconductors, highlighting their signatures and implications for experimental detection.

Findings

Half-vortices exhibit distinctive spectral signatures in STM.

Violations of inversion symmetry are associated with topological defects.

The Fermi surface topology of Bogoliubov quasiparticles is characterized in PDW phases.

Abstract

Pair density waves (PDWs) are a inhomogeneous superconducting states whose Cooper pairs possess a finite momentum resulting in a oscillatory gap in space, even in the absence of an external magnetic field. There is growing evidence for the existence of PDW superconducting order in many strongly correlated materials, particularly in the cuprate superconductors and in several other different types of systems. A feature of the PDW state is that inherently it has a CDW as a composite order associated with it. Here we study the structure of the electronic topological defects of the PDW, paying special attention to the half-vortex and its electronic structure that can be detected in STM experiments. We discuss tell-tale signatures of the defects in violations of inversion symmetry, in the excitation spectrum and their spectral functions in the presence of topological defects. We discuss the ``Fermi surface'' topology of Bogoliubov quasiparticle of the PDW phases, and we briefly discuss the role of quasiparticle interference.