| The restricted geometry of nanostructures often gives rise to novel properties and phenomena that are potentially useful in applications. Symmetry and many-electron effects can become significantly more important in determining their behaviors. In this talk, I discuss some of our recent work using theory and computation to study the properties of carbon nanostructures including carbon nanotubes, graphene, graphene nanoribbons and superlattices. These sp2-bonded nanostructures exhibit a number of unexpected behaviors – novel conductance characteristics, magnetic defect states, extraordinarily large excitonic effects in their optical response, anomalous behaviors in the dynamics of carriers (the 2D massless Dirac fermions) in graphene under an external periodic potential, electron supercollimation in graphene superlattices, and an electric field-induced half-metallic state for zigzag graphene nanoribbons, among others. The physics behind these unusual behaviors is examined. |
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