二维极限下非晶膜的动力学
Dynamics of amorphous membranes in the two-dimensional limit
AI总结：
该研究探究二维极限下非晶膜的动力学，以单层非晶碳（MAC）构建纳米鼓，观测到其谐振运动的非线性动力学特征，确立MAC为可靠纳米机电平台，开辟无序主导的纳米力学实验路径。
AI中文摘要：
原子级薄的机械谐振器主要在结晶二维（2D）材料中实现，例如石墨烯，其中长程结晶序决定了其弹性质并定义了其非线性谐振行为。将这些概念扩展到非晶二维极限在很大程度上仍未被探索。在此，我们证明单层非晶碳（MAC）形成悬浮膜，其在谐振运动的线性和非线性区域均支持光热驱动和灵敏的干涉读出。我们解析了MAC纳米鼓中的热机械运动、驱动谐振和多模光谱。基频振动模式的频率对应异常低的预应力，使单层MAC纳米鼓处于几何非线性、应力异质性和模式耦合在相对较低的驱动功率下出现的区域。相应地，我们观察到显著的非线性动力学，包括硬化、软化和混合杜芬响应、非线性阻尼、参量激发模式以及模式间耦合的特征。这些结果确立MAC为一种可靠的纳米机电平台，并为二维非晶极限下由无序主导的纳米力学开辟了一条实验途径。
英文摘要：
Atomically thin mechanical resonators have been realized predominantly in crystalline two-dimensional (2D) materials, such as graphene, where long-range crystalline order sets their elastic properties and defines their nonlinear resonant behavior. Extending these concepts to the amorphous 2D limit has remained largely unexplored. Here, we demonstrate that monolayer amorphous carbon (MAC) forms suspended membranes that support optothermal actuation and sensitive interferometric readout across both linear and nonlinear regimes of its resonant motion. We resolve thermomechanical motion, driven resonances, and multimode spectra in MAC nanodrums. The frequencies of fundamental vibration modes correspond to unusually low pretensions, placing monolayer MAC nanodrums in a regime where geometric nonlinearities, stress heterogeneity, and mode coupling emerge at comparatively low drive powers. Consistently, we observe pronounced nonlinear dynamics, including hardening, softening, and mixed Duffing responses, nonlinear damping, parametrically excited modes, and signatures of intermodal coupling. These results establish MAC as a robust nanoelectromechanical platform and open an experimental route to disorder-governed nanomechanics in the 2D amorphous limit.
