Akhiezer mechanism dominates relaxation of propagons in amorphous material at room temperature

Propagons play an important role in tuning the thermal conductivity of nanostructured amorphous materials. Although advances have been made to quantitatively evaluate relaxation time propagons with molecular dynamics, underlying mechanism remains unexplored. Here, we investigate process silicon, silica, and silicon nitride at room temperature terms Akhiezer model, parameters which were evaluated by performing lattice dynamics analysis. The results show that model can well reproduce experimental obtained various types measurement methods, indicating dominates temperature. Moreover, appropriate sound speed is around 80% Debye comparable transversal speed. We also reveal diffusons’ contribution these materials similar, 1 W/m K, whereas propagons’ overall heat conduction varies significantly depending on materials: it 30% silica but as high 70% nitride. offers a deeper understanding propagon transport attenuation