Topological vortices in chiral gauge theory of graphene

Generation mechanism of energy gaps between conductance and valence bands is at the centre of the study of graphene material. Recently, Chamon, Jackiw et al. proposed a mechanism of using a Kekulé distortion background field φ   and its induced gauge potential AiAi to generate energy gaps. In this paper, various vortex structures inhering in this model are studied. Regarding φ   as a generic background field rather than a fixed Nielson–Oleson type distribution, we have found two new types of vortices on the graphene surface—the velocity field vortices and the monopole-motion induced vortices—from the inner structure of the potential AiAi. These vortex structures naturally arise from the motion of the Dirac fermions instead of from the background distortion field.