▎ 摘　　要

Effect of defects on negative differential thermal resistance (NDTR) is investigated using non-equilibrium molecular dynamics method for the symmetric graphene nanoribbons (GNRs) with defects. Remarkably, it is found that NDTR will disappear as the number of defects increases. In addition, heat current of GNRs with defects is larger than that of the pristine GNRs when the temperature difference is larger. The results are explained qualitatively utilizing the theory of phonon spectra mismatch. The work may be useful in designing thermal-nano devices on the basis of GNRs. (C) 2014 AIP Publishing LLC.