Effect of topological line defects on electron-derived thermal transport in zigzag graphene nanoribbons

We investigate electron-derived thermal transport in zigzag graphene nanoribbons (ZGNRs) with topological line defects (TLDs) including tetragon-TLD (4-TLD), octagon-TLD (8-TLD), double pentagons and octagon-TLD (558-TLD), as well as double pentagons and double heptagons-TLD (5757-TLD). Results show that these TLDs can efficiently modify the band structure and electron-derived thermal conductance. Near the intrinsic Fermi level, the normalized thermal conductance for both 4-TLD and 8-TLD (both 558-TLD and 5757-TLD) is the same as (higher than) that of pristine ZGNRs. When the Fermi level is far above the top of the first subband, the normalized thermal conductance for four TLDs is much lower than the pristine value. We also show that the TLDs' position dependence of the normalized thermal conductance exhibits the similar trend for different types of TLDs, but this trend strongly depends on the Fermi level. A brief analysis of these results is given.

Near the intrinsic Fermi level, the normalized thermal conductance for both 4-TLD and 8-TLD is the same as that pristine ZGNRs regardless of the introduction of 4-TLD and 8-TLD. However, both 558-TLD and 5757-TLD can enhance the electron-derived thermal conductance due to the additional contribution of the defective state. When the Fermi level is far above the top of the first subband, the normalized thermal conductance for these four TLDs is much lower than the corresponding value for pristine ZGNRs, since the high-energy electronic structure for the TLDs is less dispersive compared to pristine ZGNRs.281