Thermoelastic Damping in Nanomechanical Resonators with Finite Wave Speeds

Abstract

The operation of micro-=nanobeams vibrating at very high frequencies, such as encountered in micro-=nanoelectromechanical systems (MEMS=NEMS), hinges on the minimization of intrinsic material losses. We study the associated thermoelastic damping in such beams from the standpoint of a generalized theory of thermoelasticity with one relaxation time. Some of our results relate to: (i) the cooling (instead of heating) in the compressed surface of the beam; (ii) the existence of not one damping peak appearing in the classical theory, but many peaks, with a decreasing amplitude as the frequency tends to infinity; (iii) the relevance of thermoelasticity with finite wave speeds for frequencies on the order of 1012Hz.