Hi again, and thanks. I think I am getting there, so for a system with two bands each row has 4 elements which corresponds to 2 left-going and 2 right-going modes. Is that correct?
And the orbitals in this case, corresponds to spin? I haven't implemented spin or anything manually to the model, is this done by Kwant by default? The output I get is a 2x4-matrix. Is the output wavefunction a spinor? Best, Camilla -----Original Message----- From: Joseph Weston [mailto:joseph.westo...@gmail.com] Sent: 16. november 2016 15:13 To: Camilla Espedal <camilla.espe...@ntnu.no> Cc: kwant-discuss@kwant-project.org Subject: Re: [Kwant] Question about lead_info[].wave_functions[] Hi, > Thank you. This might be a silly question, but what is the meaning of > orbitals here? Is it not only 1? When I say "orbitals" it's really a shorthand for "degrees of freedom". If you have a lead with 2 sites in the unit cell, and each one has a single degree of freedom associated with it (i.e. the onsites are just numbers) then the wavefunction would be a vector with 2 entries. If you have, say, spin 1/2 particles, then each site would have 2 degrees of freedom associated with it (spin up & spin down). In the same way, if a site really represents an atom, then your "internal degrees of freedom" could be the different atomic orbitals (s, p, d etc.). Of course, Kwant makes no assumptions about what these degrees of freedom actually mean -- it is up to the user to define what they mean by describing the appropriate Hamiltonian. > The orbital elements seem to be conjugate of each other. I think you are looking at the wrong axis of the `wave_functions` array. The *first* axis runs over the orbitals, and the *second* axis runs over the modes. For a given band, I would expect the left- and right-propagating modes to be conjugates of each other, as they are related by time-reversal symmetry (unless you have some terms in your Hamiltonian that break this, but I think not). Does that clarify? Joe
