Nonmonotonous Magnetic Field Dependence and Scaling of the Thermal Conductivity for Superconductors with Nodes of the Order Parameter

TL;DR

This paper introduces a new mechanism explaining the nonmonotonous magnetic field dependence of thermal conductivity in superconductors with nodes, aligning with experimental data and revealing different behaviors for pairing types.

Contribution

It identifies a novel nonmonotonous relaxation time mechanism in superconductors with nodes and demonstrates scaling behavior for specific pairing symmetries at low fields and temperatures.

Findings

Nonmonotonous relaxation time due to unitary scatterers.

Qualitative agreement with experimental data for UPt_3.

Scaling of thermal conductivity for E_{2u} pairing at low fields and temperatures.

Abstract

We show that there is a new mechanism for nonmonotonous behavior of magnetic field dependence of the electronic thermal conductivity of clean superconductors with nodes of the order parameter on the Fermi surface. In particular, for unitary scatterers the nonmonotony of relaxation time takes place. Contribution from the intervortex space turns out to be essential for this effect even at low temperatures. Our results are in a qualitative agreement with recent experimental data for superconducting UPt_3. For E_{2u}-type of pairing we find approximately the scaling of the thermal conductivity in clean limit with a single parameter x=T/T_c\sqrt{B_{c2}/B} at low fields and low temperatures, as well as weak low-temperature dependence of the anisotropy ratio K_{zz}/K_{yy} in zero field. For E_{1g}-type of pairing deviations from the scaling are more noticeable and the anisotropy ratio is essentially temperature dependent.