Dear Kwant users,
I write for advices concening apparent
problems that I encountered programming with Kwant.
I would like to calculate quantities related to transport (e.g. conductivity,
Fano factor,.....) in 2D and 3D lattice systems hosting Dirac / Weyl points.
I have tried to implement a couple of examples of semimetals with Kwant,
where the lattices (scattering regions) are taken square or cubic,
and the leads attached on entire faces of the lattices.
I assumed both open and periodic (in the directions orthogonal to the leads)
boundaries conditions for the lattices and for the leads.
Generally, I have found strange things, like
sudden falls to zero of the conductivities within the energies of the
scattering areas, or suspicious conductivity asymmetries
around the energies of the cones, even if the lattice spectra are symmetric.
I am reasonably sure that the Hamiltonians are written correctly in Kwant,
at least because I checked separately the spectra of the scattering zones
and of the leads, comparing them with the analytics.
Discussing at a conference,
I got aware vaguely about possible problems
that may arise when one wants to
discretize in real space an Hamiltonian originally written in
the space of momenta (also continuous).
This is exaclty what I have done always;
notice that I performed the discretization by hand, without
exploiting the routine in Kwant.
Do you know about similar issues with semimetals ?
Do you have some advices ?
Thank you very much to everybody and best regards,