New scenario of sound damping in glasses

An understanding of the difference between the universal low-temperature properties of amorphous solids and crystalline solids requires an explanation of the stronger damping of long-wavelength phonons in amorphous solids. A quartic scaling of the sound attenuation coefficient on the wavevector, which was deduced from experiments and later found support in a number of theoretical and simulation investigations, has recently been questioned in a new large scale simulation. Subsequently, quartic scaling was found in another large scale simulational study. These recent conflicting results reopened the problem of the wavevector dependence of sound attenuation. Here, we study simulated glasses with a wide range of stability and demonstrate the existence of a quartic scaling regime of the sound attenuation coefficient on wavevector in very stable glasses but not in poorly annealed glasses. For transverse sound waves in all glasses examined, we observe a long-wavelength quadratic scaling regime whose upper wavevector cutoff increases with increasing stability. Our results demonstrate an intimate connection between stability and sound damping in glasses and a new, unexpected damping scenario.