We evaluate the charge carrier transmission across asymmetric grain boundaries (GB) in a graphene lattice within the Landauer-Büttiker formalism. We employ a tight-binding model for C-based materials that accounts for lattice strain introduced by topological defects, such as grain boundaries. In particular, we investigate electronic transmission across grain boundaries found to be stable up to high temperatures. Our calculations suggest that the introduction of GBs generally preserves the zero-transport gap property of pristine graphene. However, only some specific asymmetric GBs open a moderate transport gap, which can be as high as ≈ 1.15 eV . We find that the GBs that introduce a transport gap are characterized by the existence of a mismatch along the GB. Indeed, the magnitude of this mismatch appears to be the main structural variable that determines the transport gap size, with greater mismatch resulting in larger transport gaps. Finally, we find that the presence of GBs reduces considerably electron transmission, and less so hole transmission.

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We present evidence of strong steric interference in bilayer graphene containing offset point dislocations. Calculations are carried out with Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) using the Long-Range Carbon Bond-Order Potential (LCBOP) potential of Los et al.. We start by validating the potential in the harmonic response by comparing the predicted phonon dispersion curves to experimental data and other potentials. The requisite force constants are derived by linearization of the potential and are presented in full form. We then continue to validate the potential in applications involving the formation of dislocation dipoles and quadrupoles in monolayer configurations. Finally, we evaluate a number of dislocation quadrupole configurations in monolayer and bilayer graphene and document strong steric interactions due to out-of-plane displacements when the dislocations on the individual layers are sufficiently offset with respect to each other.

Abstract. In the field of electronics, due to its excellent mechanical and electrical properties