Low-Temperature Properties of a Superconducting Disordered Metal

Abstract

Specific heat $C_p$ and thermal conductivity $\kappa$ measurements between 0.1 and 10 K on the superconducting ($T_c=2.53\mathrm{}$ K) and structurally disordered metal ${\mathrm{Zr}}_{0.7}$ ${\mathrm{Pd}}_{0.3}$ exhibit an approximately linear term in $C_p$ and a $T^{1.9}$ dependence of $\kappa$ below $T_c$. The magnitudes of these terms are close to those found for insulating glasses, thereby suggesting that disorder-induced localized excitations exist at similar densities in very different classes of disordered solids.