Thanks! On Mon, Apr 19, 2021 at 2:49 AM Antonio Manesco <antonio...@usp.br> wrote:
> Sorry, I think you meant the diagonal elements of the Hamiltonian matrix. > You do that with the hamiltonian_submatrix method ( > https://kwant-project.org/doc/1/reference/generated/kwant.system.System). > > On Sun, 18 Apr 2021, 19:15 Antonio Manesco, <antonio...@usp.br> wrote: > >> Hi Nafise >> >> You can access the s-matrix elements using the submatrix method ( >> https://kwant-project.org/doc/latest/reference/generated/kwant.solvers.common.SMatrix >> ). >> >> Best, >> Antonio >> >> On Sun, 18 Apr 2021, 11:55 Nafise Nouri, <nafise.n...@gmail.com> wrote: >> >>> Dear all, >>> I need to access the matrix diagonal element in the scattering region in >>> my program. Is there any way to access the matrix diagonal element in the >>> following program or do I have to use numpy? >>> >>> Best regard, >>> >>> import kwant >>> import matplotlib.pyplot as plt >>> import tinyarray >>> import numpy as np >>> import math >>> from functools import partial >>> from kwant.physics import dispersion >>> >>> #mport matplotlib >>> >>> d=1.42; >>> a1=d*math.sqrt(3); >>> >>> latt = kwant.lattice.general([(a1,0),(0.5*a1,a1*math.sqrt(3)/2)], >>> [(0,0),(0,a1/math.sqrt(3))]) >>> a,b = latt.sublattices >>> syst= kwant.Builder() >>> >>> >>> #................................................................................... >>> def rectangle(pos): >>> x, y = pos >>> z=x**2+y**2 >>> return -4*3*a1<y<4.5*3*a1 and -4.5*d<=x<4.5*d >>> >>> syst[a.shape(rectangle, (2,2))] = 0 >>> syst[b.shape(rectangle, (2,2))] = 0 >>> >>> #nearest >>> neighbors............................................................. >>> syst[[kwant.builder.HoppingKind((0,0),a,b)]] = -2.7 >>> syst[[kwant.builder.HoppingKind((0,1),a,b)]] = -2.7 >>> syst[[kwant.builder.HoppingKind((-1,1),a,b)]] = -2.7 >>> >>> ax=kwant.plot(syst); >>> >>> sym = kwant.TranslationalSymmetry(latt.vec((-1,0))) >>> >>> sym.add_site_family(latt.sublattices[0], other_vectors=[(-1, 2)]) >>> sym.add_site_family(latt.sublattices[1], other_vectors=[(-1, 2)]) >>> lead = kwant.Builder(sym) >>> >>> >>> def lead_shape(pos): >>> x, y = pos >>> return -4*3*a1<y<4.5*3*a1 >>> >>> lead[a.shape(rectangle, (2,2))] = 0 >>> lead[b.shape(rectangle, (2,2))] = 0 >>> >>> >>> #nearest >>> neighbors............................................................. >>> lead[[kwant.builder.HoppingKind((0,0),a,b)]] = -2.7 >>> lead[[kwant.builder.HoppingKind((0,1),a,b)]] = -2.7 >>> lead[[kwant.builder.HoppingKind((-1,1),a,b)]] = -2.7 >>> >>> syst.attach_lead(lead) >>> syst.attach_lead(lead.reversed()) >>> ax=kwant.plot(syst); >>> >>> >>> ###############################################################################\ >>> fsys = syst.finalized() >>> Sites= list(fsys.sites) #list of all the sites in the scattering region >>> number_of_sites=len(Sites) >>> >>> >>> bands = dispersion.Bands(fsys.leads[0]) >>> momenta = np.linspace(-np.pi,np.pi, 100) >>> energies=[bands(k) for k in momenta] >>> >>> np.savetxt('band1.txt',bands(-np.pi)) >>> >>> >>> plt.plot(momenta,energies) >>> >>> plt.xlabel(r'$K$') >>> plt.ylabel(r'$band structure (eV)$') >>> plt.ylim((-0.5,0.5)) >>> plt.savefig('bandsarmBiStrain.pdf') >>> plt.show() >>> >>
