Session L37: Focus Session: Vacancy and Grain Boundary Effects in Graphene

8:00 AM–11:00 AM, Wednesday, March 5, 2014
Room: 705/707

Sponsoring Unit: DMP
Chair: Kurt Gaskill, U.S. Naval Research Laboratory

Abstract ID: BAPS.2014.MAR.L37.15

Abstract: L37.00015 : Thermal and electrical conductivity of defective graphene: From grain boundaries to haeckelite

10:48 AM–11:00 AM

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  Zhen Zhu
    (Michigan State University)

  Zacharias G. Fthenakis
    (Michigan State University)

  David Tomanek
    (Michigan State University)

We study the effect of structural defects on the electronic and thermal conductivity of graphene from first-principles calcluations. After optimizing defective structures using density functional theory, we describe ballistic charge transport using the non-equilibrium Green's function formalism and thermal transport using non-equilibrium molecular dynamics simulations. We find that both the electrical conductance $G$ and thermal conductivity $\lambda$ depend sensitively on the nature, concentration and arrangement of 5-7 and 5-8 defects, which may form grain boundaries in the honeycomb lattice of graphene or, at large concentrations, convert it to haeckelite. Lines of defects in graphene turn both $\sigma$ and $\lambda$ anisotropic. In a defective structure of graphene nanoribbons interconnected by haeckelite strips, the electrical conductance $G$ increases, whereas the thermal conductivity is quenched by up to 1-2 orders of magnitude, mainly due to the reduced phonon mean free path. We conclude that defects play a profound role in the electrical and thermal transport of graphene.

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