I am a PhD student of Hong Kong University of Science and Technology. I
want to use KWANT to caculate Hall resistance of a Hall bar structure.We
can get the conductance between 6 electrodes, but how to get hall
resistance? Can you give me some help? Thank you very much.
Dear Kwant developer,
Thank you for your effort in developing Kwant.
I have a question about the definition of the direction of momentum in the smatrix.lead_info. Assume a lead lies along the y direction with primitive vector (0,1). The symmetry operation of a lead is (0,1) if the lead goes towards the positive direction and is (0,-1) if the lead goes towards the negative direction. For the momenta contained in smatrix.lead_info for these two leads , do they use the same coordinate system? Positive momenta mean the direction (0,1), negative momenta mean the direction (0,-1). For velocity, in smatrix.lead_info, it has nothing to do with the coordinate system. Positive means outgoing, negative means incoming in the lead.
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I would like to plot bandstructure of a graphene lead with electron and hole structure (i.e. norbs=2),
while distinguishing (e.g. with color) between electron and hole bands.
The lattice is defined as
lat = kwant.lattice.general([(sqrt(3)*1/2, 1/2), (0, 1)],
[(0, 0), (1/(2*sqrt(3)),1/2)], norbs=2)
the lead is created as
lead0 = kwant.Builder(sym_lead)
lead0[a.shape(lead0_shape,(0,0))] = -EF * tau_z
lead0[b.shape(lead0_shape,(0,0))] = -EF * tau_z
lead0[lat.neighbors()] = -t * tau_z
Then the bandstructure is obtained as
bands = kwant.physics.Bands(lead0.finalized())
momenta = numpy.linspace(-pi, pi, 201)
energies = [bands(k) for k in momenta]
Is there an easy way to get the bands just for electrons? Something like
"bands = kwant.physics.Bands(lead0.finalized(), orbital = 0)"
or for holes
"bands = kwant.physics.Bands(lead0.finalized(), orbital = 1)"
Dear Kwant users,
The Kwant team in Grenoble has recently hosted a masters student, Paul
who has taken the initiative and written a Kwant "FAQ" that is meant to
complement the existing Kwant tutorial and documentation.
The aim of this document is to be very explicit in explaining common
and misunderstandings that people new (and not so new!) to Kwant make.
was new to Kwant at the start of his internship, he was in a good
identify what was not clear and what could be explained in more detail.
You can see a preliminary version of the FAQ on a test deployment of the
website . At this stage we are eager to collect feedback to see what
be improved. You can either reply by email in this thread, or join the
discussion on the open merge request on the Kwant gitlab .
When I calculate the scattering matrix (kwant.smatrix()) it seems that only one CPU (I have 12 in total) is working, while the others are idle. Is there a (simple) way to make all the CPUs work together when using kwant.smatrix ? Maybe similar improvements can be done for kwant.wave_function ? I am using Ubuntu 16.10.
I know this has been discussed before a long time ago, but I was wondering if there was some progress on this, now that Kwant 1.3 is released.
All the best,
Dear Kwant user,
I am beginner at using kwant and I need to calculate DOS of graphene adatom.
I was wondering whether these is possibility to set the potential function for this system?
I am so confused of the wave function we get from :
wf = kwant.solvers.default.wave_function(some_sys, some_energy)
and the eigen vector we can get form the；
because we can reshape the eigen vector and get its norm,
hence give us the wave mode distribution along the wire, which is the
So I thought that is the wave function. But when I tried the
I got something different. I want to make these two consistent with
each other. So I wonder
what the relation between these two ways.
Dear kwant users and developers,
I am planning to study transport through the double-stranded DNA molecule.
I was wondering if this geometry has been already implemented in kwant.
Thank you for any help