We describe a method and its implementation for calculating electronic
structure and electron transport without approximating the structure using
periodic super-cells. This effectively removes spurious periodic images and
interference effects. Our method is based on already established methods
readily available in the non-equilibrium Green function formalism and allows
for non-equilibrium transport. We present examples of a N defect in graphene,
finite voltage bias transport in a point-contact to graphene, and a
graphene-nanoribbon junction. This method is less costly, in terms of
CPU-hours, than the super-cell approximation.Comment: 8 pages, 7 figure
