Fernando de Juan — Page 5

arXiv2008

Dislocations in graphene

We study the stability and evolution of various elastic defects in a flat graphene sheet and the electronic properties of the most stable configurations. Two types of dislocations are found to be stable: "glide" dislocations consisting of heptagon-pentagon pairs, and "shuffle" dislocations, an octagon with a dangling bond. Unlike the most studied case of carbon nanotubes, Stone Wales defects are unstable in the planar graphene sheet. Similar defects in which one of the pentagon-heptagon pairs is displaced vertically with respect to the other one are found to be dynamically stable. Shuffle dislocations will give rise to local magnetic moments that can provide an alternative route to magnetism in graphene.

cond-mat.mes-hall↗

arXiv2007

Charge inhomogeneities due to smooth ripples in graphene sheets

We study the effect of the curved ripples observed in the free standing graphene samples on the electronic structure of the system. We model the ripples as smooth curved bumps and compute the Green's function of the Dirac fermions in the curved surface. Curved regions modify the Fermi velocity that becomes a function of the point on the graphene surface and induce energy dependent oscillations in the local density of states around the position of the bump. The corrections are estimated to be of a few percent of the flat density at the typical energies explored in local probes such as scanning tunnel microscopy that should be able to observe the predicted correlation of the morphology with the electronics. We discuss the connection of the present work with the recent observation of charge anisotropy in graphene and propose that it can be used as an experimental test of the curvature effects.

cond-mat.str-el↗