Hi Everyone! I want to solve basic problem of transmission of electron through a potential barrier without taking into account any effects contacts. But the influence of leads in all the examples provided in kwant documentation definitely exists. For example, in the quantum wire case leads are set the same way as the scattering region, that why I expect the transmission should be obtained identically one (for any energy of incident electron). This means that kwant takes into account also some regions outside the leads e.g. bulk metal contacts. Also I modified the quantum well example like this: def plot_transmission(syst, energies, welldepth): data = [] for energy in energies: smatrix = kwant.smatrix(syst, energy, args=[-welldepth]) data.append(smatrix.transmission(1, 0)) data = np.array( data ) pyplot.figure() pyplot.plot(energies, data) pyplot.xlabel("Energy [t]") pyplot.ylabel("Transmission") pyplot.show() and in the main function make a call plot_transmission(syst, [0.01 * i for i in range(1,100)], 0.0) As a result some dependence on E is obtained even for the case of zero depth of the potential whell and it is not identically one. So, is it possible to obtain in Kwant the transmission coefficient through the defined in the scattering region structures which is not affected by anything else? Sincerely, Jambulat Basaev