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arXiv · 1808.10606

Renormalizations in unconventional superconducting states of Ce$_{1-x}$Yb$_{x}$CoIn$_{5}$

Zhaofeng Ding·Jian Zhang·Cheng Tan·Kevin Huang·Ivy Lum·Oscar O. Bernal·Pei-Chun Ho·Douglas E. MacLaughlin·M. Brian Maple·Lei Shu
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Abstract

We have measured the superconducting penetration depth~$Λ(T)$ in the heavy-fermion/intermediate-valent superconducting alloy series~Ce$_{1-x}$Yb$_x$CoIn$_5$ using transverse-field muon spin relaxation, to study the effect of intermediate-valent Yb doping on Fermi-liquid renormalization. From $Λ(T)$ we determine the superfluid density $ρ_s(T)$, and find that it decreases continuously with increasing nominal Yb concentration~$x$, i.e., with increasing intermediate valence. The temperature-dependent renormalization of the "normal" fluid density~$ρ_N(T) = ρ_s(0) - ρ_s(T)$ in both the heavy-fermion and intermediate valence limits is proportional to the temperature-dependent renormalization of the specific heat. This indicates that the temperature-dependent Fermi-liquid Landau parameters of the superconducting quasiparticles entering the two different physical quantities are the same. These results represent an important advance in understanding of both intermediate valence and heavy-fermion phenomena in superconductors.

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Zhaofeng Ding, Jian Zhang, Cheng Tan, Kevin Huang, Ivy Lum, Oscar O. Bernal, Pei-Chun Ho, Douglas E. MacLaughlin, M. Brian Maple, Lei Shu. 2019-01-31. Renormalizations in unconventional superconducting states of Ce$_{1-x}$Yb$_{x}$CoIn$_{5}$. https://doi.org/10.1103/physrevb.99.035136

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