Hi Lorenzo, Indeed, you are right; please see for example this tutorial: https://kwant-project.org/doc/1/tutorial/discretize#limitations-of-discretization
Best, Anton On Tue, 18 Jan 2022 at 16:31, Lorenzo BAGNASACCO <lorenzo.bagnasa...@sns.it> wrote: > Dear Kwant community, > > > Thanks for the quick reply. > > I plot the band structure and I obtaine the figure I attached. For a > free-particle I expect a band structure like quadratic dispersion (E \sim > k^2). The plot of structure band is nearly quadraic. Is it due to > discretization of the system ? So it means that the wave-function sent to > the left lead (in my example) is not a free-plane-wave ? Is there a way to > control the wave-function injected in the lead ? > > Yours sincerely > > Lorenzo Bagnsacco > > Il giorno mar 18 gen 2022 alle ore 15:40 Anton Akhmerov < > anton.akhmerov...@gmail.com> ha scritto: > >> Hi Lorenzo, >> >> You need to compute the transmission at an energy where the leads have >> modes. At E = 10 in your system there aren't any. >> >> Plotting the band structure of the leads helps. Check out also the Kwant >> tutorial at https://kwant-project.org/doc/1/tutorial/ >> >> Best, >> Anton >> >> On Tue, 18 Jan 2022 at 15:37, Lorenzo BAGNASACCO < >> lorenzo.bagnasa...@sns.it> wrote: >> >>> Dear Kwant community, >>> >>> I am a physics student and I am approaching to Kwant to solve simple >>> problems of scattering. >>> I am new in Kwant and, for this reason, I'm trying to use Kwnat for >>> basic problems of scattering. >>> The most simple problem in my mind is the scattering of a plane-wave (1 >>> dimension) from the left of a potential barrier. If we now suppose the >>> potential barrier is 'zero' everywhere, the scattering matrix, according to >>> the scattering theory, should be 'S={{0,1},{1,0}}'. >>> If I try to compute the reflection and transmission coefficient, I >>> obtained the correct values (1 for reflection and 0 for transmission). But >>> it occurs only for some energies. For example in the code I attached, if I >>> put the value of '10' in 'S=kwant.solvers.default.smatrix(syst,10)' I >>> obtaine for reflection and transmission the value of '0'. Where is my >>> errors? And, is there a way to print the entire elements of the scattering >>> matrix ? >>> >>> Yours sincerely >>> >>> Lorenzo Bagnasacco >>> >>>