We present a theoretical derivation of acoustic phonon damping in amorphous solids based on the nonaffine response formalism for the viscoelasticity of amorphous solids. The analytical theory takes into account the nonaffine displacements in transverse waves and is able to predict both the ubiquitous low-energy diffusive damping similar to k (2), as well as a novel contribution to the Rayleigh damping similar to k (4) at higher wavevectors and the crossover between the two regimes observed experimentally. The coefficient of the diffusive term is proportional to the microscopic viscous (Langevin-type) damping in particle motion (which arises from anharmonicity), and to the nonaffine correction to the static shear modulus, whereas the Rayleigh damping emerges in the limit of low anharmonicity, consistent with previous observations and macroscopic models. Importantly, the k (4) Rayleigh contribution derived here does not arise from harmonic disorder or elastic heterogeneity effects and it is the dominant mechanism for sound attenuation in amorphous solids as recently suggested by molecular simulations.
Theory of sound attenuation in amorphous solids from nonaffine motions / M. Baggioli, A. Zaccone. - In: JOURNAL OF PHYSICS. CONDENSED MATTER. - ISSN 0953-8984. - 34:21(2022 May 24), pp. 215401.1-215401.10. [10.1088/1361-648X/ac5d8b]
Theory of sound attenuation in amorphous solids from nonaffine motions
A. Zaccone
Ultimo
2022
Abstract
We present a theoretical derivation of acoustic phonon damping in amorphous solids based on the nonaffine response formalism for the viscoelasticity of amorphous solids. The analytical theory takes into account the nonaffine displacements in transverse waves and is able to predict both the ubiquitous low-energy diffusive damping similar to k (2), as well as a novel contribution to the Rayleigh damping similar to k (4) at higher wavevectors and the crossover between the two regimes observed experimentally. The coefficient of the diffusive term is proportional to the microscopic viscous (Langevin-type) damping in particle motion (which arises from anharmonicity), and to the nonaffine correction to the static shear modulus, whereas the Rayleigh damping emerges in the limit of low anharmonicity, consistent with previous observations and macroscopic models. Importantly, the k (4) Rayleigh contribution derived here does not arise from harmonic disorder or elastic heterogeneity effects and it is the dominant mechanism for sound attenuation in amorphous solids as recently suggested by molecular simulations.File | Dimensione | Formato | |
---|---|---|---|
JPCM-120073_revised_clean.pdf
Open Access dal 25/05/2023
Tipologia:
Post-print, accepted manuscript ecc. (versione accettata dall'editore)
Dimensione
402.01 kB
Formato
Adobe PDF
|
402.01 kB | Adobe PDF | Visualizza/Apri |
Baggioli_2022_J._Phys. _Condens._Matter_34_215401.pdf
accesso riservato
Tipologia:
Publisher's version/PDF
Dimensione
1.04 MB
Formato
Adobe PDF
|
1.04 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.