Abstract
We have measured the superconducting penetration depth in the heavy-fermion/intermediate-valent superconducting alloy series using a transverse-field muon spin relaxation to study the effect of intermediate-valent Yb doping on Fermi-liquid renormalization. From we determine the superfluid density and find that it decreases continuously with increasing nominal Yb concentration , i.e., with increasing intermediate valence. The temperature-dependent renormalization of the “normal” fluid density 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.
- Received 31 August 2018
- Revised 3 January 2019
DOI:https://doi.org/10.1103/PhysRevB.99.035136
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