Akhiezer damping in nanostructures
K Kunal and NR Aluru, PHYSICAL REVIEW B, 84, 245450 (2011).
Dissipation in a nanomechanical resonator under the application of a nearly uniform strain field is investigated using molecular dynamics simulations. Under the application of a uniform strain field and in the frequency range studied, we expect Akhiezer damping to be the dominant loss mechanism. The scaling of energy dissipation rate with frequency for the bulk case and a finite-sized nanostructure are studied and the results are explained by Akhiezer damping. The size effect on the dissipation rate is also investigated. The results show a significant role of the surface on the dissipation rate. An increase in the Q factor with a decrease in thickness of the structure is observed for a certain range. Below some critical thickness, the trend reverses, indicating multiple roles of the surface contributing to the dissipation process.
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