Hi Luca

Dear all,

I am trying to obtain the coefficients of the transmission matrix (fine, so far.....) and to related them to the modes of the leads.

This is covered in the FAQ [1]. You can use 'lead.modes()' to get the mode wavefunctions, and the scattering matrix entries are ordered in the same way as the modes. i.e. the columns are ordered as the incoming modes of the associated leads, and the rows are ordered as the outgoing modes of the associated leads.

In particular, I would like to know the momenta of these modes (supposing periodic conditions along the directions orthogonal to the leads). Is it possible ?

I'm not sure why the periodic boundary conditions are relevant? 'lead.modes()' will give you the momentum along the translational symmetry direction. Happy Kwanting, Joe [1]: https://kwant-project.org/doc/1/tutorial/faq#how-does-kwant-order-the-propag...