Abstract
Carbon nanotubes (CNTs) have attracted much attention as a thermoelectric material. Although CNTs have large lattice thermal conductivity, CNT-based composites are promising candidates for thermoelectric material because the phonon transport is suppressed by scattering at contacts between CNTs. Therefore, thermoelectric properties at contacts between CNTs have mainly been studied in previous studies. However, deep understanding in the effect of defects and strain on the thermoelectric properties of CNTs themselves is important to improve the efficiency and reliability of thermoelectric devices. In this study, the effects of vacancies and uniaxial compressive strain are analyzed using nonequilibrium molecular dynamics and nonequilibrium Green's function method. We found that the figure of merit is significantly reduced by a small amount of vacancies and buckling deformation. Our finding indicates that thermoelectric properties of CNTs can be modified by controlling the density of vacancies and local strain field in CNTs.
