Universality in heavy-fermion systems with general degeneracy

TL;DR

This paper proposes a new universal relation between resistivity and specific heat coefficients in heavy-fermion systems with arbitrary degeneracy, improving upon the traditional Kadowaki-Woods relation.

Contribution

The authors introduce a modified relation that accounts for degeneracy, providing a better universal description across various heavy-fermion systems.

Findings

The Kadowaki-Woods relation breaks down for large degeneracy systems.

The new relation shows excellent agreement with experimental data across all degeneracies.

The proposed universal relation simplifies understanding of heavy-fermion behaviors.

Abstract

We discuss the relation between the T^{2}-coefficient of electrical resistivity $A$ and the T-linear specific-heat coefficient $\gamma$ for heavy-fermion systems with general $N$, where $N$ is the degeneracy of quasi-particles. A set of experimental data reveals that the Kadowaki-Woods relation; $A/\gamma^{2} = 1*10^{-5} {\mu\Omega}(K mol/mJ)^{2}$, collapses remarkably for large-N systems, although this relation has been regarded to be commonly applicable to the Fermi-liquids. Instead, based on the Fermi-liquid theory we propose a new relation; $\tilde{A}/\tilde{\gamma}^2=1\times10^{-5}$ with $\tilde{A} = A/(1/2)N(N-1)$ and $\tilde{\gamma} = \gamma/(1/2)N(N-1)$. This new relation exhibits an excellent agreement with the data for whole the range of degenerate heavy-fermions.