Breakdown of Shear Stiffness in Amorphous Ga

Abstract

The transverse and longitudinal sound velocities in amorphous and recrystallized Ga films were measured by tunable monochromatic phonons. The transverse sound velocity was found to be smaller by a factor of 2.8 in the amorphous phase, while there was no significant change for longitudinal phonons. Comparing the result with specific heat data gives no evidence for the existence of localized states.