Explanation for the universal low-temperature and dynamical properties of a particular glass.

Abstract

We present new measurements of the time-dependent specific heat of cubic (KBr${)}_{0.5}$(KCN${)}_{0.5}$. Using a microscopic model of the tunneling centers (180\ifmmode^\circ\else\textdegree\fi{} ${\mathrm{CN}}^{\mathrm{\ensuremath{-}}}$ reorientations) we provide a unified explanation of this specific heat and the low-frequency dielectric loss. Thus, in a crystal exhibiting the universal low-temperature thermal properties and the broad low-frequency dielectric relaxations characteristic of glasses, we have explained both using a microscopic tunneling model.