The elastic behaviour of InBi single crystals

Ultrasonic wave velocities have been measured by the pulse echo technique at 15MHz in single crystals of InBi grown by zone-melting. The elastic stiffness constant set has been computed from the velocity data by a least-mean-squares procedure. The elastic behaviour of this metallic compound is quite different in kind from that of the semiconducting III-V crystals; the volume compressibility does not follow Keyes' generalisation for the other III-V compounds. The elastic properties of InBi have been found to show the characteristics of a layer-like crystal with weak interlayer binding; this finding is illustrated by the linear compressibilities and by a compilation of cross-sections of the wave velocity and Young's modulus surfaces. The Debye temperature is 115°K.