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.
@article{arxiv.1905.11113,
title = {Removing all periodic boundary conditions: Efficient non-equilibrium Green function calculations},
author = {Nick Papior and Gaetano Calogero and Susanne Leitherer and Mads Brandbyge},
journal= {arXiv preprint arXiv:1905.11113},
year = {2019}
}