Hello everyone, I have defined two semi-infinite contacts in my system as follows: -------------------------------------------------------------------- def lead_shape(p): x, y, z = p return -10 < x < 10 and -6 < y < 6 and 0 < z < 30 sym_lead = kwant.TranslationalSymmetry(lattice.vec((-6, 0, 0))) lead = kwant.Builder(sym_lead) lead[lattice.shape(lead_shape, (0, 0, 15))] = 0 -------------------------------------------------------------------- Is there an easy way to calculate any reflections from the lead back into the conductor? I mean, ideally, I would like all electrons entering the contacts to stay there. Regards Eleni -- Dr. Eleni Chatzikyriakou Computational Physics lab Aristotle University of Thessaloniki elchatz@auth.gr - tel:+30 2310 998109