The third-order elastic constants of indium antimonide

Abstract

The six third-order elastic constants of a pure specimen of indium antimonide have been measured at room temperature These have been obtained from measurements of the change in acoustic velocity with applied stress using an improved version of the ultrasonic `sing-around' system. Possible contributions to the constants other than those arising directly from interatomic forces are considered and are shown to be negligible in our measurements The results are interpreted and discussed in terms of a recent theory in which the third-order constants of covalent materials are dominated by three anharmonic force constants between first- and second-nearest neighbours.