Phonon Transport of Zigzag/Armchair Graphene Superlattice Nanoribbons
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Nanostructured thermoelectric materials are promising for modulating physical properties to achieve high thermoelectric performance. In this paper, thermal transport properties of armchair/zigzag graphene superlattice nanoribbons (A/Z graphene SLNRs) are investigated by performing nonequilibrium molecular dynamics simulations. The target of the research is to realize low thermal conductivity by introducing single-vacancy point defects. Our simulations demonstrate that the thermal conductivity of A/Z graphene SLNRs depends nonmonotonically on periodic length. In addition, introducing single-vacancy point defects into the superlattice nanoribbons could decrease the phonon tunneling in superlattice nanoribbons, so that the thermal conductivity could be reduced further. Furthermore, a monotonic dependence of the thermal conductivity of A/Z graphene SLNRs with length of zigzag part in periodic length is discovered. This phenomenon is explained by performing phonon property analysis. Our simulations deliver a detailed phonon transport in A/Z graphene SLNRs and provide useful guidance on how to engineer the thermal transport properties of A/Z graphene SLNRs for applications of nanoribbon-related devices in thermoelectrics.
KeywordsGraphene superlattice nanoribbon Molecular dynamics simulation Phonon transport Single-vacancy point defect
This research was supported by the NSF of China under Grants Nos. 11304059, 11602149, the NSF of Heilongjiang Province of China under Grants No. QC2015001, and the International Postdoctoral Exchange Fellowship Program No. 20140016.
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