Experimental verification of Herring's theory of anharmonic phonon relaxation: TeO2

The attenuation of a narrow Fresnel-diffracted monochromatic beam of longit udinal phonons propagating along the [001] axis is measured as a function o f the frequency and the temperature in a single crystal of paratellurite (T eO2). The attenuation varies according to omega(a)T(b) With a = 1.84 +/- 0. 20 and b = 2.81 +/- 0.20 below about 53 K, and according to omega(a)T with a = 1.87 +/- 0.20 above this temperature. These results confirm Herring's t heory for anharmonic phonon decay in anisotropic crystals, with L + ST --> FT the relevant three-phonon process. [S0163-1829(99)09501-6].