Hi, I noticed that no one ever replied to the following message...
dielectric_hjz...@126.com wrote: > Dear kwanters, I am using kwant for handle a k.p Hamiltonian, for the > conductance calculations. I start from a k.p model, and transform it > to a tight-binding model using kwant.continuum tools [procedures > listed here https://kwant-project.org/doc/1/tutorial/discretize]. Now > I want to study the conductance of the system under magnetic > field. I try to do Peierls substitution for hoppings between site > i and site j (i-j being parallel to the lead). However, I find that > using the kwant.continuum scheme, there are no information regarding > the lattice information such as "lat = kwant.lattice.honeycomb() > ". This prevents the application of Peierls substitution by the > following way: > > _____________________________ def hopx(site1, site2, B): y = site1.pos[1] > return - np.exp(-1j * B * y) > > syst[kwant.builder.HoppingKind((1, 0), lat.a, lat.b)] = hopx > ____________________________ > > My question is how to add magnetic field during the calculations > for the systems generated from a continuum model by kwant.continuum? I can think of several possible solutions: • If the magnetic field you want is constant, you may be able to incorporate an appropriate vector potential (using an appropriate gauge) into the Hamiltonian that you discretize. I haven’t tried this, but I don’t see why this shouldn’t work. • This is a bit of a hidden functionality (you can discover it by having a glimpse at the source of the discretizer module), but you can actually print a builder returned by the discretizer. This should allow to reimplement the same model with added magnetic field. You can also look at the output of discretize_symbolic. (This should be similar to printing the builder.) • Kwant actually has functionality for adding an arbitrary magnetic field to a system: https://kwant-project.org/doc/1/pre/whatsnew/1.4#automatic-peierls-phase-calculation However this is most likely overkill if you are only interested in a constant magnetic field. Christoph
smime.p7s
Description: S/MIME cryptographic signature
