A Study on Phonon Transmission of (10,0) Silicon Nanotube with Atomic Vacancies

A systematic computer simulation has been carried out to find out the exclusive phonon properties of both pristine and vacancy defected (10,0) semiconductor zigzag silicon nanotube for the first time. It is found that phonons are scattered into other phonon states due to vacancy. Vacancy generates degenerate phonon branches. The simulated phonon density of states shows softening of high-frequency phonons. Quite significant reduction in the phonon transmission is observed over the whole frequency spectrum with the introduction of vacancy. Quasi ballistic phonon conduction is noticed instead of the presence of vacancy for low-frequency region. Again, high-frequency phonon localization is found in vacancy defected nanotube. The thermal conductivity decreases in a large amount with only 1 % vacancy. Moreover, entropy of the vacancy defected system is examined.