权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Nonlinear coarse-graining of Graphene nanoresonators: realistic boundary conditions and the origin ofnonlinear damping

石墨烯纳米谐振器的非线性粗粒化：现实边界条件和非线性阻尼的起源

基本信息

批准号：
217693948
负责人：
Dr. David Kauzlaric
金额：
--
依托单位：
Courant Institute of Mathematical Sciences
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2015-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/217693948?language=en
关键词：
Nonlinear coarse graining Graphene nanoresonators

项目摘要

The project will develop a highly efficient simulation platform for Graphene nanoresonators, i.e., for oscillating systems consisting of a single molecule, which is a laterally clamped membrane of one atomic layer of Graphite. For this purpose we reduce the computationally expensive atomistic Molecular dynamics models by means of the Mori-Zwanzig formalism to models with a few relevant degrees of freedom, which can be computed more efficiently. The discarded degrees of freedom act in the reduced model as fluctuations and dissipation (damping) of the oscillations. In contrast to the previous project, this project focusses especially on the challenge to represent correctly the influence of the nonlinearities and of the boundary conditions (the clamping) on the form of the fluctuating and dissipative forces acting on the relevant variables. Considering the clamping conditions explicitly implies to take the specific substrate material (Copper, Nickel, Silicon, etc.) into account, where the Graphene membrane is attached. The nonlinearities and clamping conditions are essential for the correct prediction of the resonator's quality factor, i.e., the prediction of the time before significant loss of vibrational energy. The quality factor determines the precision of the resonator to measure atomic masses, displacements, frequencies, to detect molecules, or for frequency filtering. Understanding the origins of dissipation and of its nonlinearities on an atomic scale, and the transfer of this knowledge into a reduced model will open the door to an efficient and direct atomistic design of resonance properties, for example to minimise losses, or to shift them into uncritical frequencies.

该项目将为石墨烯纳米谐振器开发一个高效的模拟平台，即由单个分子组成的振荡系统，该分子是一个石墨原子层的横向夹紧膜。为此，我们通过 Mori-Zwanzig 形式将计算成本高昂的原子分子动力学模型减少为具有一些相关自由度的模型，从而可以更有效地计算。丢弃的自由度在简化模型中充当振荡的波动和耗散（阻尼）。与之前的项目相比，该项目特别关注正确表示非线性和边界条件（夹紧）对作用于相关变量的脉动力和耗散力形式的影响的挑战。考虑夹紧条件明确意味着要考虑石墨烯膜所附着的特定基材材料（铜、镍、硅等）。非线性和钳位条件对于正确预测谐振器的品质因数（即预测振动能量显着损失之前的时间）至关重要。品质因数决定了谐振器测量原子质量、位移、频率、检测分子或频率滤波的精度。了解原子尺度上耗散及其非线性的起源，并将这些知识转移到简化模型中，将为高效、直接的共振特性原子设计打开大门，例如最大限度地减少损失，或将它们转变为非关键频率。