Iranian Nanotechnology SocietyInternational Journal of Nanoscience and Nanotechnology1735-700410320140901Ab Initio Study of Chirality Effects Onphonon Spectra, Mechanical and Thermal Properties of Nearly Samediameter Single Wall Carbon Nanotubes1631709094ENH.TashakoriPhysics Department, Computational Physics Lab, Qom Branch, Islamic Azad University,
Qom, I.R. IranB.Khoshnevisan1-Physics Department, Computational Physics Lab, Qom Branch, Islamic Azad University,
Qom, I.R. Iran
2- Faculty of Physics, University of Kashan, Kashan, I. R. IranF.KanjouriFaculty of Physics, Kharazmi University , Tehran , I. R. IranZ. S.NaghaviFaculty of Physics, University of Kashan, Kashan, I. R. IranJournal Article20140112In this paper, we have used density functional perturbation theory (DFPT) and Pseudo-potential method to calculate the phonon spectrum, phonon density of states (DOS), specific heat capacity and mechanical properties of (5,5) armchair and (9,0) zigzag Single Wall Carbon Nanotubes (SWCNTs). Our calculations show that Young’s modulusfor (5,5) and (9,0) nanotubesare higher than 1TPa. We have also shown that the value of compressive Young’s modulus for (5,5) nanotube isgreater thanthat for (9,0) nanotube while thevalue of tensile Young’s modulus for (9,0) nanotubeisgreater than that for(5,5) nanotube. The result of our calculations shows that thespecific heat capacity of (5,5) and (9,0) nanotubes coincides, therefore we may conclude that thespecific heat capacity of nanotubes is independent of their chirality. Furthermore we have found that the atoms in the armchair nanotubes are positioned as close as possible in the direction of the nanotube axis, therefore they could have more resistant against compressive pressurehttps://www.ijnnonline.net/article_9094_3da65416b36cd5189c31b2eb81862309.pdf