Thermal conductivities of Li, Na, K, and Agβ-alumina below 300 K

Abstract

The thermal conductivities of single-crystal Li, Na, K, and Ag $\beta$-alumina have been measured in the temperature range of $\approx 0.1-300$ K. The thermal conductivity is very sensitive to the cation present and is indicative of a broad band of excitations ($\lesssim {10}^{-21\mathrm{}}$J, $\lesssim {10}^{12}$ Hz) which scatter thermal phonons. The results are compared with a tunneling-states theory of disordered materials and with published data from specific-heat and light-scattering measurements.