Fizika Nizkikh Temperatur: Volume 46, Number 2 (February 2020), p. 138-146 ( to contents , go back )
Universal temperature dependence of the thermal conductivity of clathrate compounds, molecular crystals and glasses at low temperatures
O.A. Korolyuk, A.I. Krivchikov, and O.O. Romantsova
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Nauki Ave., Kharkiv 61103, Ukraine
Received October 9, 2019, published online December 27, 2019
The experimental data on the dependence of low-temperature thermal conductivity on temperature κ(T) of some representatives of disordered complex crystals (tetrahydrofuran, methane, xenon clathrate hydrates, Ba8Ga16Ge30 of p-type and Sr8Ga16Ge30 clathrate compounds, YSZ ceramics, as well as molecular structural glasses of 1-propanol, glycerol and D-ethanol), showing glass-like behavior of κ(T), and some representatives of regular complex crystals (tetrahydrofuran clathrate hydrate, Ba8Ga16Ge30 of n-type clathrate compound, layered crystal CsDy(MoO4)2, 1-propanol and D-ethanol) has been analyzed in the framework of the new approach. A universal approach to the normalization of low-temperature thermal conductivity is proposed, which follows from the theoretical model of hybridized Klinger–Kosevich excitations. It is shown that the low-temperature universal behavior of the thermal conductivity of both crystalline and amorphous solids is the result of one and the same phenomenon, the hybridization of acoustic and low-lying optical branches.
Key words: universal behavior of thermal conductivity, complex crystals, clathrate hydrates, disordered solids, hybridization.