Signatures of two-level defects in the temperature-dependent damping of nanomechanical silicon nitride resonators

Thomas Faust, Johannes Rieger, Maximilian J. Seitner, Jörg P. Kotthaus, Eva M. Weig
2014 Physical Review B  
The damping rates of high quality factor nanomechanical resonators are well beyond intrinsic limits. Here, we explore the underlying microscopic loss mechanisms by investigating the temperature-dependent damping of the fundamental and third harmonic transverse flexural mode of a doubly clamped silicon nitride string. It exhibits characteristic maxima reminiscent of two-level defects typical for amorphous materials. Coupling to those defects relaxes the momentum selection rules, allowing energy
more » ... s, allowing energy transfer from discrete long wavelength resonator modes to the high frequency phonon environment.
doi:10.1103/physrevb.89.100102 fatcat:ycqdw6s47vgxhcdecplyznj3ne