SOME PECULIARITIES OF PHONON-SCATTERING BY POINT-DEFECTS IN LAYERED CRYSTALS

Experimental results of the temperature dependences of phonon thermal conductivity of some layered crystals are analyzed. It is pointed out that the nearly linear temperature dependence of thermal conductivity at low temperature has been observed in crystals with a large number o f point defects. The relaxation rates of phonons scattered by static d isplacement of atoms around point defects are calculated in the frame of a simple model of phonon dispersion, which accounts for the flexura l rigidity of the layers. It is shown that the scattering of phonons b y point defects lying between layers would cause the experimentally ob served temperature dependence of thermal conductivity.