Elastic moduli of GaAs at moderate pressures and the evaluation of compression to 250 kbar

Abstract

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 (B_T) of 746.6 kbar and its pressure derivative (∂B_T∕∂P) of 4.67 calculated using the above data, the static compression of GaAs has been computed to a pressure of 250 kbar.