2021/05/19 by Bingyu Cui, Alessio Zaccone, Cui, Bingyu +3
Engineering · Materials Science · #Acoustic Wave Phenomena Research #Composite Material Mechanics #Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Material Dynamics and Properties
paper · pdf · doi:10.48550/arxiv.2105.09393
openalex publication_date 2021/05/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In scattering experiments, the dynamical structure factor (DSF) characterizes inter-particle correlations and their time evolution. We analytically evaluated the DSF of disordered solids with disorder in the spring constant, by averaging over quenched disorder in the values of lattice bond strength, along the acoustic branch. The width of the resulting acoustic excitation peak is treated as the effective damping constant Γ(q), which we found to grow linearly with exchanged momentum q. This is verified by numerically calculating a model system consisting of harmonic linear chains with disorder in spring constant. We also found that the quenched averaging of the vibrational density of states produces a characteristic peak at a frequency related to the average acoustic resonance. Such a peak (the excess over Debye law) may be related to the "boson peak" frequently discussed in disordered solids, in our case explicitly arising from the quenched disorder in the distribution of spring constants.