Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, People's Republic of China. Institute of Structural Mechanics, Bauhaus-University Weimar, Marienstraße 15, D-99423 Weimar, Germany.
Nanotechnology. 2014 Jan 17;25(2):025501. doi: 10.1088/0957-4484/25/2/025501. Epub 2013 Dec 12.
We perform classical molecular dynamics simulation to investigate the mechanisms underpinning the unresolved, experimentally observed temperature-dependent scaling transition in the quality factors of graphene nanomechanical resonators (GNMRs). Our simulations reveal that the mechanism underlying this temperature scaling phenomenon is the out-of-plane migration of adsorbates on GNMRs. Specifically, the migrating adsorbate undergoes frequent collisions with the GNMR, which strongly influences the resulting mechanical oscillation, and thus the quality factors. We also predict a discontinuous transition in the quality factor at a lower critical temperature, which results from the in-plane migration of the adsorbate. Overall, our work clearly demonstrates the strong effect of adsorbate migration on the quality factors of GNMRs.
我们进行了经典分子动力学模拟，以研究石墨烯纳米机械谐振器（GNMR）质量因子中未解决的、实验观察到的温度相关比例转变的基础机制。我们的模拟表明，这种温度缩放现象的机制是 GNMR 上吸附物的面外迁移。具体来说，迁移的吸附物与 GNMR 频繁碰撞，这强烈影响了最终的机械振荡，从而影响了质量因子。我们还预测在较低的临界温度下，质量因子会发生不连续的转变，这是由于吸附物的面内迁移。总的来说，我们的工作清楚地表明了吸附物迁移对 GNMR 质量因子的强烈影响。
