Dear all, I am trying a graphene bulk with magnetic field, and I use spectrum = kwant.kpm.SpectralDensity(fsyst, num_vectors=None, vector_factory=s_factory, rng=0) energies, densities = spectrum() to calculate the dos and compare with some previous studies. My definition of the hopping is: def Hop_magnetic(site1,site2): B_magneic=200. # units Tesla a0=0.142 # nm x1,y1=site1.pos x2,y2=site2.pos xy=0.5*(x1+x2)*sqrt(3)*a0*(y1-y2)*sqrt(3)*a0 # the units is nm**2 phb=1j*2.*pi*B_magneic/4.135667 # phi0=h/e=4.135667*e-15 V*s return t*exp(xy*phb*0.001) I found that the effect of the magnetic field is too small and I can not obtain the correct results. Could you give me some suggestions? Best regards Khani My code is pasted: import kwant from matplotlib import pyplot from numpy import sqrt,pi,exp import numpy as np def make_system(r=8, t=1, tp=-0.1): lat = kwant.lattice.honeycomb(norbs=1) a, b = lat.sublattices def circle(pos): x, y = pos return x**2 + y**2 < 100**2 #-100