The Role of Reconstructed Surfaces in the Intrinsic Dissipative Dynamics of Silicon Nanoresonators

Dissipation in the flexural dynamics of doubly clamped nanomechanical bar resonators is investigated using molecular dynamics simulation. The dependence of the quality factor Q on temperature and the size of the resonator is calculated from direct simulation of the oscillation of a series of Si <001> bars with bare {100} dimerized surfaces. The bar widths range from 3.3 to 8.7nm, all with a fixed length of 22nm. The fundamental mode frequencies range from 40 to 90GHz and Q from 10^2 near 1000K to 10^4 near 50K. The quality factor is shown to be limited by defects in the reconstructed surface.