Steric Interference in Bilayer Graphene with Point Dislocations

Abstract

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.

Charge-carrier transmission across twins in graphene

“…It is observed that the transport gap increases up to a maximum at approximately n = 15 and subsequently decreases slightly to a constant value solely dependent on m beyond n ∼ 25. This asymptotic value for large n may be regarded as a characteristic transport gap for a given m. Coincidentally, analyses of isolated dislocation dipoles in graphene reveal that the dislocation cores cease to interact at approximately that twin width [33,45]. The opening of band gaps may be traced to localized wave functions that arise at-and bind to-dislocation cores.…”

“…In this work, we specifically focus on twinned microstructures resulting from the introduction of periodic arrays of parallel dipoles in a single graphene layer, figure 1. The energetics of these structures has been studied in [23] using the computational method presented in [33]. The method consists of a first harmonic step designed to set the desired defect structure into the lattice followed by a fully nonlinear relaxation.…”