Advances in nano-fabrication techniques has made it feasible to observe damping phenomena beyond the linear regime in nano-mechanical systems. In this work, we report cubic non-linear damping in palladium nano-mechanical resonators. Nano-scale palladium beams exposed to a H2 atmosphere become softer and display enhanced Duffing non-linearity as well as non-linear damping at ultra low temperatures. The damping is highest at the lowest temperatures of ∼110mK and decreases when warmed up-to ∼1K. We experimentally demonstrate for the first time a temperature dependent non-linear damping in a nano-mechanical system below 1 K. It is consistent with a predicted two phonon mediated non-linear Akhiezer scenario for ballistic phonons with mean free path comparable to the beam thickness. This opens up new possibilities to engineer non-linear phenomena at low temperatures.
@article{arxiv.2009.08324,
title = {Temperature Dependent Non-linear Damping in Palladium Nano-mechanical Resonators},
author = {Shelender Kumar and S. Rebari and Satyendra P. Pal and S. S. Yadav and Abhishek Kumar and § A. Aggarwal and S. Indrajeet and A. Venkatesan},
journal= {arXiv preprint arXiv:2009.08324},
year = {2021}
}