The quantum transport formalism based on tight-binding models is known to be
powerful in dealing with a wide range of open physical systems subject to
external driving forces but is, at the same time, limited by the memory
requirement's increasing with the number of atomic sites in the scattering
region. Here we demonstrate how to achieve an accurate simulation of quantum
transport feasible for experimentally sized bulk graphene heterojunctions at a
strongly reduced computational cost. Without free tuning parameters, we show
excellent agreement with a recent experiment on Klein backscattering [A. F.
Young and P. Kim, Nature Phys. 5, 222 (2009)].Comment: 5 pages, 3 figure
