[Kwant] Re: Help: Inputting Random Potential on Graphene

Dear Raymond, I think that the problem comes from the last line of your code.

syst[lat.shape(circle, (0, 0))] = onsite(bytes(3),bytes(3))

calls the function onsite with the 2 arguments you provided and then assign the result to all the sites. What you want to do is

syst[lat.shape(circle, (0, 0))] = onsite

In that case, when iterating over the sites, kwant will call the onsite function for each site. See the documentation for providing the salt parameter, e.g. https://kwant-project.org/doc/1/tutorial/spin_potential_shape in the quantum_well.py example. Best regards, Xavier

Le 12 mai 2022 à 00:26, Blackwell, Raymond a écrit :

Hello,

My name is Raymond Blackwell and I am attempting to use Kwant to simulate some experimental data. Our data involves dopant atoms intercalated under graphene, so I would like to simulate the LDOS but with a potential that randomly varies at several points within the system. I am trying to modify the code for the kernel_polynominal_method, but I cannot seem to get a random potential. I have used a similar method to randomly select a few points and modify the hopping parameter, but I am struggling with the seemingly more simple case where the potential varies.

The relevant portion of my code is below.

def make_syst(r=30, t=-1, a=1): syst = kwant.Builder() lat = kwant.lattice.honeycomb(a, norbs=1)

def circle(pos): x, y = pos return x ** 2 + y ** 2 < r ** 2 sites2 = list(syst.sites()) Random_sites= random.choices(sites2, k=10)

def onsite(site, salt): return 0.5 * kwant.digest.gauss(repr(Random_sites), salt)

syst[lat.shape(circle, (0, 0))] = onsite(bytes(3),bytes(3))

Any help is greatly appreciated!

Best, -Raymond