Nonlinear Dissipation in Nanomechanics

Dissipation of energy in micro- and nano-electromechanical resonators governs their dynamical response and limits their potential use in device applications. Quantified by the quality factor Q, dissipation (1/Q) usually occurs by energy loss mechanisms that are linear, appearing as a damping term proportional to the velocity. Mechanisms of linear dissipation in micro- and nano-mechanical resonators are well studied both theoretically and experimentally. Mechanisms of nonlinear dissipation of energy, however, are rarely studied, though their effects could be fundamentally important to the operation of numerous devices based on nonlinear resonators such as switches, signal processors, sensors, and energy harvesting systems. In a recent paper published in Applied Physics Letters, we report experimental observation of nonlinear dissipation in diamond nanoelectromechanical resonators.

In a separate paper published in Nano Letters, we report the observation of nonlinear dissipation in nanomechanical diamond resonators measured by an ultrasensitive heterodyne down-mixing piezoresistive detection technique. The combination of a hybrid structure as well as symmetry breaking clamps enables sensitive piezoresistive detection of multiple orthogonal modes in a diamond resonator over a wide frequency and temperature range. Using this detection method, we observe the transition from purely linear dissipation at room temperature to strongly nonlinear dissipation at cryogenic temperatures. At high drive powers and below liquid nitrogen temperatures, the resonant structure dynamics follows the Pol-Duffing equation of motion. Instead of using the broadening of the full width at half-maximum, we propose a nonlinear dissipation backbone curve as a method to characterize the strength of nonlinear dissipation in devices with a nonlinear spring constant.