Thermal conductivity of carbon nanotube superlattices: Comparative study with defective carbon nanotubes**Project supported by the National Natural Science Foundation of China (Grant Nos. 11404278 and 11275163) and the Science Foundation of Hunan Province, China (Grant No. 2016JJ2131).

Abstract

We use molecular dynamics simulation to calculate the thermal conductivities of (5, 5) carbon nanotube superlattices (CNTSLs) and defective carbon nanotubes (DCNTs), where CNTSLs and DCNTs have the same size. It is found that the thermal conductivity of DCNT is lower than that of CNTSL at the same concentration of Stone–Wales (SW) defects. We perform the analysis of heat current autocorrelation functions and observe the phonon coherent resonance in CNTSLs, but do not observe the same effect in DCNTs. The phonon vibrational eigen-mode analysis reveals that all modes of phonons are strongly localized by SW defects. The degree of localization of CNTSLs is lower than that of DCNTs, because the phonon coherent resonance results in the phonon tunneling effect in the longitudinal phonon mode. The results are helpful in understanding and tuning the thermal conductivity of carbon nanotubes by defect engineering.