Breakdown of universal transport in correlated d-wave superconductors

TL;DR

This paper explains the breakdown of universal thermal conductivity in underdoped cuprate superconductors as due to disorder-induced magnetic states and antiferromagnetic correlations, reconciling experimental observations with theoretical models.

Contribution

It introduces a disorder-based explanation for the violation of universality in thermal conductivity in underdoped d-wave superconductors.

Findings

Disorder-induced magnetic states cause breakdown of universality.

Antiferromagnetic correlations protect low-energy density of states.

Experimental data aligns with the proposed model.

Abstract

The prediction and observation of low-temperature universal thermal conductivity in cuprates has served as a keystone of theoretical approaches to the superconducting state, but recent measurements on underdoped samples show strong violations of this apparently fundamental property of d-wave nodal quasiparticles. Here, we show that the breakdown of universality may be understood as the consequence of disorder-induced magnetic states in the presence of increasing antiferromagnetic correlations in the underdoped state, even as these same correlations protect the nodal low-energy density of states in agreement with recent scanning tunneling experiments.