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arXiv · 1609.08714

Nonlinear damping and dephasing in nanomechanical systems

J. Atalaya·T. W. Kenny·M. L. Roukes·M. I. Dykman
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Abstract

We present a microscopic theory of nonlinear damping and dephasing of low-frequency eigenmodes in nano- and micro-mechanical systems. The mechanism of the both effects is scattering of thermally excited vibrational modes off the considered eigenmode. The scattering is accompanied by energy transfer of $2\hbar\omega_0$ for nonlinear damping and is quasieleastic for dephasing. We develop a formalism that allows studying both spatially uniform systems and systems with a strong nonuniformity, which is smooth on the typical wavelength of thermal modes but not their mean free path. The formalism accounts for the decay of thermal modes, which plays a major role in the nonlinear damping and dephasing. We identify the nonlinear analogs of the Landau-Rumer, thermoelastic, and Akhiezer mechanisms and find the dependence of the relaxation parameters on the temperature and the geometry of a system.

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J. Atalaya, T. W. Kenny, M. L. Roukes, M. I. Dykman. 2016-09-28. Nonlinear damping and dephasing in nanomechanical systems. https://doi.org/10.1103/physrevb.94.195440

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