不同温度条件下单层石墨烯纳米带弛豫性能的分子动力学研究
Relaxation properties of graphene nanoribbons at different ambient temperatures: a molecular dynamics study
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摘要: 分别采用Tersoff-Brenner势和AIREBO势,对三种长宽比的单层石墨烯纳米带在不同热力学温度(0.01—4000K)下的弛豫性能进行了分子动力学模拟.对基于两种势函数模拟的石墨烯纳米带弛豫的能量曲线和表面形貌进行了分析对比,研究了石墨烯纳米带在弛豫过程中的动态平衡过程.模拟结果表明:单层石墨烯纳米带并非完美的平面结构,边缘处和内部都会呈现一定程度的起伏和皱褶,这与已有的实验结果相符合;石墨烯纳米带的表面起伏程度随长宽比的减小而减小,并且在不同温度条件下,系统动能对石墨烯纳米带的弛豫变形的影响很大,即系统温度越高,石墨烯纳米带的弛豫变形幅度愈大;高长宽比纳米带在一定温度条件下甚至会出现卷曲现象.最后,对采用Tersoff-Brenner势和AIREBO势进行石墨烯的分子动力学模拟进行了深入分析.
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关键词:
- 石墨烯纳米带 /
- Tersoff-Brenner势和AIREBO势 /
- 弛豫性能 /
- 分子动力学模拟
Abstract: At different thermodynamic temperatures (between 0.01 and 4000 K), the relaxation properties of three kinds of graphene nanorib- bons with different aspect ratios are simulated by molecular dynamics method based on Tersoff-Brenner and AIREBO potential func- tions separately. Then we compare the energy curves and surface morphologies of nanoribbon relaxation with two kinds of potential functions, and study the dynamic equilibrium process of the graphene nanoribbons during their relaxation simulation. The simulation results show that the single layer graphene nanoribbon is not of a perfect planar structure and that a certain degree of fluctuations and folds occur at the edges and inside of nanoribbons, which are consistent with the existing experimental results; the surface fluctuation level of graphene nanoribbons decreases with the reduction of the aspect ratio, and the system kinetic energy has a dramatic influence on the relaxation deformation of the graphene nanoribbons at different temperatures, which indicates that the higher the system tem- perature, the greater the deformation is. Curl phenomenon could appear even on the surface of the nanoribbon with a high aspect ratio at a certain temperature. Finally, the simulations of graphen molecular dynamics by using the Tersoff-Brenner and AIREBO potential are deeply analyzed. -
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