High-performance solution of the transport problem in a graphene   armchair structure with a generic potential
  We propose an efficient numerical method to study the transport properties of armchair graphene ribbons in the presence of a generic external potential. The method is based on a continuum envelope-function description with physical boundary conditions. The envelope functions are computed in the reciprocal space, and the transmission is then obtained with a recursive scattering matrix approach. This allows a significant reduction of the computational time with respect to finite difference simulations. 
Demetrio Logoteta, Paolo Marconcini, Claudio Bonati, Maurizio Fagotti,   Massimo Macucci
cond-mat.mes-hall physics.comp-ph