The low-temperature thermal conductivity in polycrystalline graphene is theoretically studied. The contributions from three branches of acoustic phonons are calculated by taking into account scattering on sample borders, point defects and grain bound
aries. Phonon scattering due to sample borders and grain boundaries is shown to result in a $T^{alpha}$-behaviour in the thermal conductivity where $alpha$ varies between 1 and 2. This behaviour is found to be more pronounced for nanosized grain boundaries. PACS: 65.80.Ck, 81.05.ue, 73.43.Cd
The electronic transport properties of a metallic carbon nanotube with the five-seven disclination pair characterized by a lattice distortion vector are investigated. The influence of the disclination dipole includes induced curvature and mixing of t
wo sublattices. Both these factors are taken into account via a self-consistent perturbation approach. The conductance and the Fano factor are calculated within the transfer-matrix technique. PACS: 73.63.Fg, 72.80.Rj, 72.10.Fk
We study the electronic structure of graphene in the presence of either sevenfolds or eightfolds by using a gauge field-theory model. The graphene sheet with topological defects is considered as a negative cone surface with infinite Gaussian curvatur
e at the center. The density of electronic states is calculated for a single seven- and eightfold as well as for a pair of sevenfolds with different morphology. The density of states at the Fermi energy is found to be zero in all cases except two sevenfolds with translational factor $M eq 0$.
