I'm trying to reproduce the data from PRB 74, 205307 (2006) with Kwant. I'm having trouble extracting data from the spin up and spin down lattices.

This is how I do it:

Define two square lattices with names "up" and "down". Here's the code for the local energies:

lat_up = kwant.lattice.square(1, name="up") lat_dw = kwant.lattice.square(1, name="dw")

delta=1.1*Ny;

sys[(lat_up(x, y) for x in range(Nx) for y in range(Ny))] = 4*t sys[(lat_dw(x, y+delta) for x in range(Nx) for y in range(Ny))] = 4*t

I'm using this "delta" so that the kwant.plot(sys) show then separately.

Define separate leads for the spin up and down lattices. So I can investigate the injection of each kind of spin.

To reproduce Fig.1, panels (b) and (c), of the paper above I run

rho0=np.abs(wf(0).sum(axis=0))**2

This gives me the spin up and down projections of the wave-function injected via lead 0 (up lead). But the spin up projection is on one lattice, while the spin down is on the other lattice.

When I plot using kwant's map plot (command below), I do see exactly Fig.1(b) and (c), one in each lattice.

kwant.plotter.map(sys, rho0);

But I don't know how to extract from rho0 (or from kwant's wave-function command) the data from a given lattice.

When I try to implement a spin-orbit Hamiltonian using matrices instead of separate lattices, it is easy to split the spin up and down data using something like ldos[0::2] and ldos[1::2], since the up and down data alternate in the array. But with matrices I have no control over the spin up or down injection. So it seems that I do have to use separate lattices.

So, with separate lattices... how do I extract the data from each lattice to separate arrays?

Thanks in advance, Best regards, Gerson