Dear Sir or Madam, It seems that the number of modes from left and right are not equal while using the second nearest hopping. It should work for the first neighbor hopping but not further. You might overcome this issue by averting the use of a1 and a2 directions. You would simply add the following sym0.add_site_family(graphene.sublattices[0], other_vectors=[(-1, 2)]) sym0.add_site_family(graphene.sublattices[1], other_vectors=[(-1, 2)]) sym1.add_site_family(graphene.sublattices[0], other_vectors=[(-1, 2)]) sym1.add_site_family(graphene.sublattices[1], other_vectors=[(-1, 2)]) dum_sym.add_site_family(graphene.sublattices[0], other_vectors=[(-1, 2)]) dum_sym.add_site_family(graphene.sublattices[1], other_vectors=[(-1, 2)]) I hope this will fix your issue. Best wishes Adel Le lun. 14 juin 2021 à 05:37, <170070051@iitb.ac.in> a écrit :
Hi, The following is the error message. This can help you find out where the problem is.
Traceback (most recent call last): File "/home/bmlabserver05/Koustav/kwant_simulations-kwant_valley_branch4/kwant_simulations-kwant_valley_branch1/kwant_valley_main/silicene_lattice.py", line 168, in <module> local_dos = kwant.ldos(syst,energy=E,params=params) File "/usr/lib/python3/dist-packages/kwant/solvers/common.py", line 535, in ldos params=params)[0] File "/usr/lib/python3/dist-packages/kwant/solvers/common.py", line 191, in _make_linear_sys prop, stab = lead.modes(energy, args, params=params) File "/usr/lib/python3/dist-packages/kwant/system.py", line 253, in modes return physics.modes(ham, hop, discrete_symmetry=symmetries) File "/usr/lib/python3/dist-packages/kwant/physics/leads.py", line 1143, in modes *symmetries) File "/usr/lib/python3/dist-packages/kwant/physics/leads.py", line 923, in compute_block_modes time_reversal, chiral) File "/usr/lib/python3/dist-packages/kwant/physics/leads.py", line 818, in make_proper_modes raise RuntimeError("Numbers of left- and right-propagating " RuntimeError: Numbers of left- and right-propagating modes differ, possibly due to a numerical instability.