The elastic constants of bismuth-antimony alloy single crystals

The elastic stiffness constant tensor components of single crystals of bismuth and its alloys (3 at.%Sb, 5 at.%Sb, 7 at.%Sb and 10 at.%Sb) with antimony have been obtained between 4.2K and room temperature from measurements of ultrasonic wave velocities made by the pulse echo overlap technique. In contradiction with previous work on polycrystalline alloys the ultrasonic velocities are found to increase smoothly with antimony composition. The electronic contribution to the elastic constants is negligibly small. The temperature dependences of the elastic constants, which are remarkably similar for bismuth and the alloys, have been fitted by an anharmonic oscillator model.