Temperature dependence of ultrasonic attenuation and nonlinearity constant D for germanium

Values of the nonlinearity constant D which determines the coupling of acoustic phonons with the thermal phonons have been evaluated for the semiconducting material germanium in the temperature range 297–78.9 °K using the experimental data of second- and third-order elastic constants of this material. The temperature-dependent behavior of this constant has thus been tested for the first time on a theoretical basis through ultrasonic attenuation evaluated for high-frequency compressional waves, propagating along the 〈100〉 direction in single-crystal germanium. The results obtained are found to be in excellent agreement with the experimental values observed previously.