The Influence of Vibrational Modes on Sound Attenuation in Two Dimensional Glasses

The low temperature properties of glasses are markedly different than their crystalline counterparts. Here we study sound attenuation in two dimensional glasses in the harmonic approximation, which serves as a starting point for understanding low temperature properties of solids. We use a recently developed theory of sound attenuation [1] to determine the contribution to sound attenuation for individual vibrational modes. We find that vibrational modes that are heavily influenced by quasilocalized excitations make a relatively large contribution to sound attenuation. However, we find that the plane-wave-like vibrational modes are the dominant contribution to sound attenuation for stable two-dimensional glasses. Our work highlights the importance of understanding the influence of the full spectrum of vibrational modes on the low-temperature properties of solids.

[1] G. Szamel and E. Flenner, J. Chem. Phys. 158, 144502 (2022).