Nonlinear damping and dephasing in nanomechanical systems
Nonlinear damping and dephasing in nanomechanical systems
复制标题
DOI：
10.1103/physrevb.94.195440
复制
发表时间：
2016-11-28
影响因子：
3.7
通讯作者：
Dykman, M. I.
中科院分区：
文献类型：
--
作者：
Atalaya, Juan;Kenny, Thomas W.;Dykman, M. I.
我们提出了一个微观理论的非线性阻尼和失相的低频本征模式在纳米机械和微机械系统。这两种效应的机制是热激发的振动模式的散射所考虑的本征模式。对于非线性阻尼，散射伴随着2（h）在棒Ω（0）上的能量转移，并且对于退相是准弹性的。我们发展了一种形式主义，它允许研究空间均匀系统和具有强非均匀性的系统，这种非均匀性在热模的典型波长上是光滑的，但在它们的平均自由程上是明显的，该形式主义解释了热模的衰减，这在非线性阻尼和退相中起着重要作用。我们确定的非线性类似物的朗道-鲁默，热弹性，和Akhiezer机制，并找到依赖的弛豫参数的温度和系统的几何形状。
We present a microscopic theory of nonlinear damping and dephasing of low-frequency eigenmodes in nanomechanical and micromechanical 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 (h) over bar omega(0) for nonlinear damping and is quasielastic 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 is pronounced on their mean free path. The formalism accounts for the decay of thermal modes, which plays amajor 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.