Thermal expansion and thermal conductivity of (In$_{2}$S$_{3}$)$_{x}$ (AgIn$_{5}$S$_{8}$)$_{1-x}$ alloys

The thermal expansion and thermal conductivity of In$_{2}$S$_{3}$ and AgIn$_{5}$S$_{8}$ single-crystal compounds and (In$_{2}$S$_{3}$)$_{x}$ (AgIn$_{5}$S$_{8}$)$_{1-x}$ alloys grown by the Bridgman method are studied. It is established that the thermal-expansion coefficient linearly varies under changes in the composition parameter $x$ and the thermal conductivity has a minimum for the equimolar composition. From experimental data on the thermal-expansion coefficient, the Debye temperature and the root-mean-square (rms) dynamic displacements of atoms are calculated. It is shown that, as the content of Ag atoms in the alloys is increased, the Debye temperature increases and the rms dynamic displacements of atoms in the crystal lattice decrease.