Effect of coexisting order of various form and wave vector on low-temperature thermal conductivity in d-wave superconductors

TL;DR

This paper investigates how various forms of coexisting order in d-wave superconductors affect low-temperature thermal conductivity, revealing that the survival or gapping of nodes depends on the order's form and wave vector, with implications for cuprate experiments.

Contribution

It generalizes previous models to include a wider class of coexisting orders and identifies signatures in thermal conductivity related to nodal transitions, considering disorder effects.

Findings

Node survival depends on order form and wave vector.

Signature of nodal transition in thermal conductivity is disorder-dependent.

Deviations from universal thermal conductivity relate to coexisting order in cuprates.

Abstract

In light of recent experimental evidence of density wave order in the cuprates, we consider a phenomenological model of a d-wave superconductor with coexisting charge, spin or pair density wave order of various form and wave vector. We study the evolution of the nodal structure of the quasiparticle energy spectrum as a function of the amplitude of the coexisting order and perform diagrammatic linear response calculations of the low-temperature (universal-limit) thermal conductivity. The work described herein expands upon our past studies, which focused on a particular unit-cell-doubling charge density wave, generalizing our techniques to a wider class of coexisting order. We find that the question of whether the nodes of the d-wave superconductor survive amidst a reasonable level of coexisting order is sensitive to the form and wave vector of the order. However, in cases where the nodes do become gapped, we identify a signature of the approach to this nodal transition, in the low-temperature thermal conductivity, that appears to be quite general. The amplitude of this signature is found to be disorder-dependent, which suggests a connection between the presence of coexisting order in the underdoped cuprates and recent observations of deviations from universal (disorder-independent) thermal conductivity in the underdoped regime.