Nodal quasiparticle dynamics in the heavy fermion superconductor CeCoIn5 revealed by precision microwave spectroscopy

TL;DR

This study uses microwave spectroscopy to analyze quasiparticle dynamics in CeCoIn5, revealing similarities to cuprates like rapid scattering suppression below Tc and linear superfluid density, alongside notable multiband effects.

Contribution

First detailed microwave spectroscopy analysis of CeCoIn5's charge dynamics, highlighting its similarities and differences with high-Tc cuprates.

Findings

Rapid suppression of quasiparticle scattering below Tc

Linear temperature dependence of superfluid density

Presence of multiband effects and mass renormalization

Abstract

CeCoIn5 is a heavy fermion superconductor with strong similarities to the high-Tc cuprates, including quasi-two-dimensionality, proximity to antiferromagnetism, and probable d-wave pairing arising from a non-Fermi-liquid normal state. Experiments allowing detailed comparisons of their electronic properties are of particular interest, but in most cases are difficult to realize, due to their very different transition temperatures. Here we use low temperature microwave spectroscopy to study the charge dynamics of the CeCoIn5 superconducting state. The similarities to cuprates, in particular to ultra-clean YBa2Cu3Oy, are striking: the frequency and temperature dependence of the quasiparticle conductivity are instantly recognizable, a consequence of rapid suppression of quasiparticle scattering below Tc; and penetration depth data, when properly treated, reveal a clean, linear temperature dependence of the quasiparticle contribution to superfluid density. The measurements also expose key differences, including prominent multiband effects and a temperature dependent renormalization of the quasiparticle mass.