Effect of particle adsorption on the eigenfrequencies of nano-mechanical resonators

摘要

In the last two decades, nano-mechanical resonators have risen as highly promising devices for mass sensing due to their ultrahigh sensitivity. They can be used to measure the mass and stiffness of single particles like small pollution particles, viruses, bacteria, or even proteins. These capabilities of the nano-mechanical resonators have allowed the birth of a new type of mass spectrometry with no need of fragmentation or ionization of the sample and therefore ideal to measure big masses, where conventional mass spectrometers have important problems. The shape and modes of vibration of a nano-mechanical resonator can be very different and the advantages and drawbacks of one respect to another is still a hot topic. A unified theoretical framework to describe the effect of particle adsorption on a mechanical resonator is fundamental but still lacks in the literature. In this work, we present such a framework and examine the particular case of a rod-like particle adsorbed on a cantilever beam for flexural and torsional vibrations as well as on a disk resonator for radial breathing vibrations and compare the results with finite element simulations.