The elastic constants of GaAs from 2 K to 320 K

Abstract

The adiabatic elastic constants of GaAs (n type carrier density 1.3*10 16 cm -3 ) have been obtained between 2 K and 320 K from measurements of ultrasonic wave velocities by the pulse superposition technique. One aim has been to compare the results with the somewhat scattered data obtained at room temperature by previous workers: particular attention has been paid to estimation of the overall uncertainty in the elastic constants. At 298 K, C 11 =1.1841+or-0.0037, C 12 =0.537+or-0.016 and C 44 =0.5912+or-0.0018 in units of 10 12 dynes cm -2 . The Debye temperature (346.8 K) computed from the data extrapolated to 0 K is in excellent agreement with that (346.7 K) derived from low temperature specific heat measurements. The temperature dependence of the elastic constants have been fitted by an anharmonic oscillator model. The force constants and effective charge have been calculated on the basis of a rigid-ion model. The Gruneisen parameter, particle displacement and energy-flux vectors and cross-sections of the Young's modulus and wave velocity surfaces have been compiled.