I know that the band diagram for the SSH can be easily obtained analytically, but I was wondering how one would go about it using kwant. If I understand correctly we require a translational symmetry such as to have an infinite lattice, so I defined a lead and tried to get the band structure from there. Unfortunately my code does not work and stops with a TypeError: Expecting an instance of SiteFamily. I thought that I implemented the hopping similar to the one from the graphene tutorial. Furthermore, I am wondering whether the definition of the lattice correct actually? To me it seems that the lattice vector [1,0] leaves us on the site of the b-sublattice. If I change it to [2,0] however I get a commensurate error The code that I have so far is below. Thank you, Steffen import numpy as np import kwant t = 1 SSH = kwant.lattice.general([[1, 0]], # lattice vectors [[0,0], [1,0]]) # Coordinates of the sites) a,b = SSH.sublattices SSH_lead = kwant.Builder(kwant.TranslationalSymmetry([-1, 0])) SSH_lead[a.shape((lambda pos: abs(pos[0]) == 0), (0, 0))] = 1 SSH_lead[b.shape((lambda pos: abs(pos[0]) == 1), (0, 0))] = 1 LongBond = (((1, 0), a, b)) ShortBond = (((-1, 0), a, b)) SSH_lead[[kwant.builder.HoppingKind(*hopping) for hopping in LongBond]] = 2 SSH_lead[[kwant.builder.HoppingKind(*hopping) for hopping in ShortBond]] = 1 kwant.plot(SSH_lead) kwant.plotter.bands(SSH_lead.finalized())