Gap Symmetry of Superconductivity in UPd2Al3

TL;DR

This paper analyzes thermal conductivity data of UPd2Al3 to determine its superconducting gap symmetry, concluding it has horizontal nodes described by a specific cosine function.

Contribution

It provides a detailed analysis of experimental data to identify the horizontal node structure of the superconducting gap in UPd2Al3, advancing understanding of its pairing symmetry.

Findings

Superconducting gap has horizontal nodes.

Gap function is Δ(k) = Δ cos(2χ).

Supports specific pairing symmetry model.

Abstract

The angle dependent thermal conductivity of the heavy-fermion superconductor UPd$_2$Al$_3$ in the vortex state was recently measured by Watanabe et al. Here we analyze this data from two perspectives: universal heat conduction and the angle-dependence. We conclude that the superconducting gap function $\Delta({\bf k})$ in UPd$_2$Al$_3$ has horizontal nodes and is given by $\Delta({\bf k}) =\Delta\cos(2\chi)$, with $\chi = ck_{z}$.