Dear sir, As you said I tried the wraparound module but I got errors while diagonalizing the system. I don't know how to use this module for 3D system. Please help. The code is attached below
UserCodeError: Error occurred in user-supplied value function "f". See the upper part of the above backtrace for more information. sys=kwant.Builder(kwant.TranslationalSymmetry((0,0,-1))) lat=kwant.lattice.cubic(norbs=2) sys[(lat(x,y,0) for x in range(L) for y in range(W))]=onsite sys[kwant.builder.HoppingKind((1, 0, 0), lat, lat)] = hoppingx sys[kwant.builder.HoppingKind((0, 1, 0), lat, lat)] = hoppingy sys[kwant.builder.HoppingKind((0, 0, 1), lat, lat)] = hoppingz #lead=kwant.Builder(kwant.TranslationalSymmetry((0,0,-1))) #lead[(lat(x,y,z) for x in range(L) for y in range(W)for z in range(H))]=onsite #lead[kwant.builder.HoppingKind((1, 0, 0), lat, lat)] = hoppingx #lead[kwant.builder.HoppingKind((0, 1, 0), lat, lat)] = hoppingy #lead[kwant.builder.HoppingKind((0, 0, 1), lat, lat)] = hoppingz #sys.attach_lead(lead) #sys.attach_lead(lead.reversed()) sys = kwant.wraparound.wraparound(sys, keep=None) kwant.plot(sys) sysf=sys.finalized() ham_mat = sysf.hamiltonian_submatrix() ev = sla.eigsh(ham_mat, k=31, which='SM') evecs = ev[1] prob_dens = np.abs(evecs[:, 30])**2 #print(prob_dens) #Sites=list(sysf.sites) #rho = kwant.operator.Density(sysf) #density = rho(psi) #wf_sqr = sum(rho(psi) for psi in wf(0)) On Fri, May 8, 2020 at 3:30 AM Abbout Adel <abbout.a...@gmail.com> wrote: > Sorry, Naveen. I don't have an example ready to use. > > The idea behind is that the wraparound module helps you in getting the > homiltonian for each K point: H(kx,ky,kz) > > Diagonalizing it will give you E(kx,ky,kz) which means a point (or few > points for a multiband system) > the eigenvectors will help you to calculate the density for a given mode. > > I hope this helps, > > Adel > > On Thu, May 7, 2020 at 9:46 PM Naveen Yadav <naveengunwa...@gmail.com> > wrote: > >> Dear sir, >> Could you please provide me an working example of this type? >> >> Best Regards >> Naveen Yadav >> Research Scholar >> Department of Physics & Astrophysics >> University of Delhi >> New Delhi-110007 >> >> On Thu, May 7, 2020, 20:37 Abbout Adel <abbout.a...@gmail.com> wrote: >> >>> Hi again, >>> >>> I f you want translational symmetry, you need to use wraparound module >>> and you will need to find your result only on one unit cell. >>> You will have also to do integration on the Brillouin zone. >>> >>> I hope this helps >>> Adel >>> >>> On Thu, May 7, 2020 at 5:12 PM Naveen Yadav <naveengunwa...@gmail.com> >>> wrote: >>> >>>> Dear sir, >>>> I understand what you have said. But how can I maintain translation >>>> symmetry ?because my system is 3D and for plotting current I access the >>>> sites of 3D system using *list(sys.sites) *and plot the current for 2D >>>> slice. Please suggest me. >>>> >>>> Best Regards >>>> Naveen Yadav >>>> Research Scholar >>>> Department of Physics & Astrophysics >>>> University of Delhi >>>> New Delhi-110007 >>>> >>>> On Thu, May 7, 2020, 19:06 Abbout Adel <abbout.a...@gmail.com> wrote: >>>> >>>>> Dear Naveen, >>>>> >>>>> What you get is what is expected. You do not have translational >>>>> symmetry. >>>>> Rewrite your code by keeping only two dimensions and you will see why. >>>>> >>>>> I hope this helps, >>>>> Adel >>>>> >>>>> >>>>> On Thu, May 7, 2020 at 12:52 PM Naveen Yadav <naveengunwa...@gmail.com> >>>>> wrote: >>>>> >>>>>> Dear KWANT Developers, >>>>>> I am trying to plot the current density. The procedure is >>>>>> straightforward. I have attached leads to the scattering region (leads >>>>>> have >>>>>> same onsite and hopping as of the scattering region) as >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> *sys[(lat(z,y,x) for z in range(H) for y in range(W)for x in >>>>>> range(L))]=onsitesys[kwant.builder.HoppingKind((1, 0, 0), lat, lat)] = >>>>>> hoppingzsys[kwant.builder.HoppingKind((0, 1, 0), lat, lat)] = >>>>>> hoppingysys[kwant.builder.HoppingKind((0, 0, 1), lat, lat)] = >>>>>> hoppingxlead=kwant.Builder(kwant.TranslationalSymmetry((1,0,0)))lead[(lat(z,y,x) >>>>>> for z in range(H) for y in range(W)for x in >>>>>> range(L))]=onsitelead[kwant.builder.HoppingKind((1, 0, 0), lat, lat)] = >>>>>> hoppingzlead[kwant.builder.HoppingKind((0, 1, 0), lat, lat)] = >>>>>> hoppingylead[kwant.builder.HoppingKind((0, 0, 1), lat, lat)] = >>>>>> hoppingxsys.attach_lead(lead, >>>>>> add_cells=80)sys.attach_lead(lead.reversed())* >>>>>> [image: image.png] >>>>>> As you can see from the plot there is a discontinuity in the plot at >>>>>> (W=20). Why it is so even if the scattering region and leads have same >>>>>> onsite and hopping and there is translation symmetry throughout ? >>>>>> >>>>>> -- >>>>>> Best Regards, >>>>>> Naveen Yadav >>>>>> Research Scholar >>>>>> Department of Physics & Astrophysics >>>>>> University Of Delhi >>>>>> New Delhi-110007 >>>>>> >>>>> >>>>> >>>>> -- >>>>> Abbout Adel >>>>> >>>> >>> >>> -- >>> Abbout Adel >>> >> > > -- > Abbout Adel > -- Best Regards, Naveen Yadav Research Scholar Department of Physics & Astrophysics University Of Delhi New Delhi-110007
