Rostamiyan Y, Mohammadi V, Hamed Mashhadzadeh Amin
Department of Mechanical Engineering, Sari Branch, Islamic Azad University, Sari, Iran.
Department of Mechanical Engineering, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran.
J Mol Model. 2020 Mar 12;26(4):76. doi: 10.1007/s00894-020-4328-5.
Single-, double-, and triple-walled beryllium oxide nanotubes (BeONTs) along with BeO nanopeapods were simulated and geometrically optimized under the density functional theory (DFT) framework to investigate their Young's modulus, electronic properties, and stability. We found better properties in single-walled nanotubes, either their electronic or mechanical properties, than other mentioned nanotubes. Increase in the radius and inter-wall distance made an overall decrease in the Young's modulus of SW and DW BeONTs. The highest obtained modulus of SWBeONTs and DWBeONTS was calculated for structures (14,0) and (8,0)@(14,0) with the magnitudes of 700.12 Gpa and 712.24 Gpa, respectively. In addition, increasing the wall number from one to two resulted to significant growth in Young's modulus of DWBeONTs while created no significant difference between DWBeONTs and TWBeONTs. Bandgap energy of single-walled nanotubes was higher than those of double- and triple-walled nanotubes, and the bandgap showed consistent soar in both SW and DW BeONTs via increase in the radius and inter-wall distance, respectively. Furthermore, considering nanopeapods with various interlayer distances revealed that the Young's modulus and energy gap behavior of these structures were similar to what we observed in SWBeONTs. However, nanopeapods showed weaker mechanical and semiconducting properties compared with SWBeONTs. Moreover, calculating the formation energies of all under consideration structures revealed a reduction of formation energy via an increase in the dimension of single-walled nanotubes, an increase in the dimension of nanotubes via adding more walls, and an increase in the dimension of peapod structures as well, and the bigger structures are more stable than smaller ones.
在密度泛函理论（DFT）框架下，对单壁、双壁和三壁氧化铍纳米管（BeONTs）以及氧化铍纳米豆荚进行了模拟和几何优化，以研究它们的杨氏模量、电子性质和稳定性。我们发现，单壁纳米管在电子或机械性能方面比其他提及的纳米管具有更好的性能。SW和DW BeONTs的半径和壁间距离增加，导致杨氏模量整体下降。SWBeONTs和DWBeONTS的最高模量分别是针对结构(14,0)和(8,0)@(14,0)计算得出的，大小分别为700.12 GPa和712.24 GPa。此外，壁数从一增加到二导致DWBeONTs的杨氏模量显著增长，而DWBeONTs和TWBeONTs之间没有显著差异。单壁纳米管的带隙能量高于双壁和三壁纳米管，并且通过分别增加半径和壁间距离，SW和DW BeONTs的带隙均呈现一致的上升趋势。此外，考虑具有不同层间距离的纳米豆荚表明，这些结构的杨氏模量和能隙行为与我们在SWBeONTs中观察到的相似。然而，与SWBeONTs相比，纳米豆荚的机械和半导体性能较弱。此外，计算所有考虑结构的形成能表明，通过增加单壁纳米管的尺寸、通过添加更多壁来增加纳米管的尺寸以及增加豆荚结构的尺寸，形成能都会降低，并且更大的结构比较小的结构更稳定。
