Comment on "Spectroscopic Evidence for Multiple Order Parameter Components in the Heavy Fermion Superconductor CeCoIn$_5$"

TL;DR

This paper critically evaluates recent spectroscopic data on CeCoIn$_5$, arguing that the claims of d-wave pairing and multiple order parameters are not supported by the presented evidence.

Contribution

It provides a critical analysis challenging previous claims of multiple order parameters and d-wave symmetry in CeCoIn$_5$ based on point-contact spectroscopy data.

Findings

The data do not conclusively support d-wave pairing symmetry.

The evidence for multiple coexisting order parameters is not justified.

The authors call for more rigorous analysis before confirming these claims.

Abstract

Recently, Rourke et al. reported point-contact spectroscopy results on the heavy-fermion superconductor CeCoIn$_5$ [1]. They obtained conductance spectra on the c-axis surfaces of CeCoIn$_5$ single crystals. Their major claims are two-fold: CeCoIn$_5$ has i) d-wave pairing symmetry and ii) two coexisting order parameter components. In this Comment, we show that these claims are not warranted by the data presented. [1] Rourke et al., Phys. Rev. Lett. 94, 107005 (2005).