Low-Energy Excitations in(KBr)1−x (KCN)xin the Orientational Glass State

The thermal conductivity of single-crystal ${\left(\mathrm{KBr}\right)}_{1-x} {\left(\mathrm{KCN}\right)}_x$, $0.05<~x<~0.5$, in the temperature range 0.08-100 K shows behavior characteristic of amorphous solids. The low-temperature specific heats ($T<\mathrm{}2.5\mathrm{}$ K), measured on long (∼ 50 s) and on short (< 0.2 ms) time scales, also are identical to those found in amorphous solids. It is proposed that the KBr-KCN system provides a connecting link between the low-energy excitations in amorphous solids and in spin-glasses.