论文标题
从随机初始配置中形成无定形碳多壁纳米管
Formation of amorphous carbon multi-walled nanotubes from random initial configurations
论文作者
论文摘要
从初始随机构型开始，使用高斯近似电势[phys [phys]，已经模拟了多达四个墙壁和大小范围为200至3200个原子的无定形碳纳米管（A-CNT）。 Rev. B 95，094203（2017）]。通过机器学习随机森林技术预测了成功模拟A-CNT所需的重要变量（例如密度，高度和直径）。使用密度函数代码验证了模型$ \ textit {ex post facto} $。 A-CNT模型范围为0.55 nm-2 nm宽，平均壁间间距为0.31 nm。讨论了A-CNT中的拓扑缺陷，并观察到了新的缺陷构型。讨论了这些阶段中的状态和定位的电子密度，并将$π$子空间中的DeLabalized电子鉴定为层间内聚会的重要因素。电子电导率的空间投影有利于沿连接的轴向传输，而网络的非甲状腺大部分则阻碍或分叉电子传输。计算了状态的振动密度，并可能是该材料的实验测试指纹和低频径向呼吸模式的出现。使用Green-Kubo公式计算300 K处的热导率。
Amorphous carbon nanotubes (a-CNT) with up to four walls and sizes ranging from 200 to 3200 atoms have been simulated, starting from initial random configurations and using the Gaussian Approximation Potential [Phys. Rev. B 95, 094203 (2017)]. The important variables (like density, height, and diameter) required to successfully simulate a-CNTs, were predicted with a machine learning random forest technique. The models were validated $\textit{ex post facto}$ using density functional codes. The a-CNT models ranged from 0.55 nm - 2 nm wide with an average inter-wall spacing of 0.31 nm. The topological defects in a-CNTs were discussed and new defect configurations were observed. The electronic density of states and localization in these phases were discussed and delocalized electrons in the $π$ subspace were identified as an important factor for inter-layer cohesion. Spatial projection of the electronic conductivity favors axial transport along connecting hexagons, while non-hexagonal parts of the network either hinder or bifurcate the electronic transport. A vibrational density of states was calculated and is potentially an experimentally testable fingerprint of the material and the appearance of a low-frequency radial breathing mode was discussed. The thermal conductivity at 300 K was calculated using the Green-Kubo formula.
