Experimental evidence for predicted universal behavior in low-temperature Kondo lattices

Abstract

We have previously shown that the $\frac{1}{N}$ expansion of the Kondo lattice leads to the following predictions concerning the heavy-Fermi-liquid state: (i) the low-temperature specific heat behaves as $C_v={}_{\gamma }{}^{}{}_{}{}^{}T\propto \frac{T}{{\overline{T}}_k}$ with corrections $\Delta C_v={\left(\frac{T}{{\overline{T}}_k}\right)}^3\mathrm{In}\left(\frac{T}{{\overline{T}}_k}\right)$, (ii) the zero-temperature spin susceptibility $\chi \propto \frac{1}{{\overline{T}}_k}$, and (iii) the resistivity $\rho \propto {\left(\frac{T}{{\overline{T}}_k}\right)}^2$. These results all contain a unique energy scale ${\overline{T}}_k$. Here we analyze recent pressure-dependent specific-heat measurements on U${\mathrm{Pt}}_3$ combined with $\chi$ and $\rho$ data to confirm the scaling of these quantities with one strongly pressure-dependent energy scale ${\gamma }^{-1\mathrm{}}$. This picture is further supported by evidence of systematic scaling of $\chi$ and $\rho$ with $\gamma$ throughout the entire class of heavy-fermion compounds. This behavior, along with other experimental observations, suggests that the low-$T$ properties of U${\mathrm{Pt}}_3$ do not derive from ferromagnetic spin fluctuations.