Values of wave velocities and elastic moduli at 25°C were measured for hydrostatic pressures to 20 000 psi (excess over 1 atm). Variations of velocities and moduli at 1 atm were obtained over a temperature range of +50°C to −195.8°C. Adiabatic stiffness moduli (units of 1012 dyn/cm2), their pressure derivatives, and their temperature coefficients (units of 10−5/C), are shown below for 1 atm and 25°C. ModulusValuePressure derivativesTemperature coefficientc1110.79±0.055.98±0.7−1.37±0.2c12 1.24±0.053.06±0.7−5.70±1.5c44 5.78±0.022.98±0.3−1.25±0.1

Ultrasonic wave velocities and elastic moduli for high purity silicon (resistivity ∼400 Ω-cm) have been measured as a function of hydrostatic pressure and temperature in the ranges 0–30 000 psi (0–2100 kg/cm2) and − 195.8° to 25°C. Variations of moduli with pressure are found to be nearly independent of temperature in the range listed. For 25°C(Δc11/Δp)=4.33, (Δc12/Δp)=4.19, (Δc44/Δp)=0.80, (ΔK/Δp)=4.24. For − 195.8°C(Δc11/Δp)=4.29, (Δc12/Δp)=4.20, (Δc44/Δp)=0.75, (ΔK/Δp)=4.23.

Ultrasonic wave velocities in single-crystal quartz have been measured as a function of temperature and pressure by means of a pulse superposition method described in J. Acoust. Soc. Am. 33, 12 (1961). In order to make good use of all the experimental data, a set of "adjusted" velocities and initial pressure derivatives was obtained which satisfies all the cross-checks exactly, while minimizing a weighted sum of the squares of the adjustments from the measured values. These adjusted values were then used to calculate the elastic moduli as functions of temperature and pressure. Values of "zero-field" moduli at zero pressure and the initial pressure derivatives determined in this way are shown below.

Experimental techniques for determining third-order moduli of single crystals by means of ultrasonic wave propagation are described. Results for silicon and germanium demonstrate a good degree of self-consistency among the basic experimental data obtained with both hydrostatic and uniaxial pressure. In units of 1012 dyn/cm2 and for 25°C, the third-order moduli are: ModulusValue for SiValue for GeC111−8.25±0.10−7.10±0.06C112−4.51±0.05−3.89±0.03C123−0.64±0.10−0.18±0.06C144+0.12±0.25−0.23±0.16C166−3.10±0.10−2.92±0.08C456−0.64±0.20−0.53±0.07Thermodynamic definitions for the moduli (K. Brugger, Phys. Rev. 133, A1611 (1964)] have been used.

Ultrasonic wave velocities in GaAs have been measured at 25°C as a function of hydrostatic pressure. The adiabatic ``zero-electric-field'' stiffness moduli calculated from these velocities are as follows: c11=1.1877± 0.0006, c12=0.5372±0.0009, c44=0.5944±0.0003. All moduli are in units of 1012 dyn/cm2 and are based on a density of 5.3169 g/cm3 taken as exact with respect to estimates of errors. Hydrostatic pressure derivatives for c11, c12, and c44, are, respectively, 4.63±0.03, 4.42±0.05, and 1.10±0.02. From the isothermal bulk modulus (BT) of 746.6 kbar and its pressure derivative (∂BT/∂P) of 4.67 calculated using the above data, the static compression of GaAs has been computed to a pressure of 250 kbar.