Superconducting gap structure of the 115's revisited

TL;DR

This paper uses density functional theory to analyze the superconducting gap structure in 115 heavy fermion superconductors, suggesting both d-wave and extended s-wave symmetries are plausible based on electronic structure calculations.

Contribution

It provides a theoretical investigation into the pairing symmetry of 115 superconductors, highlighting the possibility of extended s-wave order parameters alongside the traditional d-wave.

Findings

Both d_{x^2-y^2} and extended s-wave gaps are plausible.

The pairing interaction peaks at ( extpi, extpi,q_z) wavevector.

Results are consistent with some experimental observations.

Abstract

Density functional theory calculations of the electronic structure of Ce- and Pu-based heavy fermion superconductors in the so-called 115 family are performed. The gap equation is used to consider which superconducting order parameters are most favorable assuming a pairing interaction that is peaked at (\pi,\pi,q_z) - the wavevector for the antiferromagnetic ordering found in close proximity. In addition to the commonly accepted $d_{x^2-y^2}$ order parameter, there is evidence that an extended s-wave order parameter with nodes is also plausible. We discuss whether these results are consistent with current observations and possible measurements that could help distinguish between these scenarios.