DFT COMBINED WITH NEGF BASED TRANSPORT PROPERTY CALCULATION OF DISTORTED 2,2 ZIGZAG GRAPHENE NANORIBBONS

Deepesh Bhardwaj

Volume : IV, Issue : XII, December - 2015

DFT COMBINED WITH NEGF BASED TRANSPORT PROPERTY CALCULATION OF DISTORTED 2,2 ZIGZAG GRAPHENE NANORIBBONS

Deepesh Bhardwaj

Abstract :

Because of the extraordinary versatility of nanomaterials which reveal a rich polymorphism of various allotropes exhibiting each possible dimensionality: fullerene molecule (0D), nanotubes and graphene ribbons (1D), graphite platelets (2D), and nano–diamond (3D) exhibiting different physical and chemical properties, carbon nanostructures are playing an important role in nanoscience and nanotechnology. Graphene ribbons were originally introduced as a theoretical model by Mitsutaka Fujita and co–authors to examine the edge and nanoscale size effect in grapheme. Graphene nanoribbons (also called nano–graphene ribbons), often abeviated GNRs, are strips of graphene with ultra–thin width (<50 nm). Transport calculations are carried out within the framework of density functional theory (DFT) combined with nonequiliium Green’s function (NEGF) method as implemented in the Atomistix ToolKit (ATK) software package. A narrow ribbon with chiral indices (2, 2) corresponding to a zigzag graphene nanoribbon, 8 carbon atoms wide have been design using the builder tool of ATK. The parameters are: Aligned unit cell vector C with n=2, m=2 zigzag edge 8 atom wide with bond length 1.42086A?. The Stone−Wales defect by rotating a bond 45?, 90? and 135? have been created and the resultant transmission spectra shows a sharp scattering region .15eV above fermi level in comparision to the graphene nanoribbons without distortion.