Low-Temperature Properties of a Superconducting Disordered Metal

Abstract

Specific heat ${C}_{p}$ and thermal conductivity $\ensuremath{\kappa}$ measurements between 0.1 and 10 K on the superconducting (${T}_{c}=2.53$ 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 $\ensuremath{\kappa}$ 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.