Experimental verification of Herring's theory of anharmonic phonon
relaxation: TeO2
E. P. N. Damen, A. F. M. Arts, and H. W. de Wijn
Faculty of Physics and Astronomy, and Debye Research Institute, Utrecht
University, P.O. Box 80.000, 3508 TA Utrecht, The Netherlands
The attenuation of a narrow Fresnel-diffracted monochromatic beam of
longitudinal phonons propagating along the [001] axis is measured as a
function of the frequency and the temperature in a single crystal of
paratellurite (TeO2). The attenuation varies according to
\omegaaTb with a = 1.84 ± 0.20 and
b = 2.81 ± 0.20 below about 53 K, and according to
\omegaaT with a = 1.87 ± 0.20 above this
temperature. These results confirm Herring's theory for anharmonic phonon
decay in anisotropic crystals, with L + ST \rightarrow FT the relevant
three-phonon process.