Dear All, How to calculate the current-voltage characteristics in graphene nanoribbon. calculated the conductance with respect to energy. I have the following code for graphene nanoribbon. how to calculate the current with respect to voltage in this example. import kwant import numpy as np from matplotlib import pyplot import matplotlib.pyplot as plt import numpy as np import numpy.linalg as npl import scipy.sparse.linalg as sla pi=np.pi ############################################## structure ######################## Wnr=10 lnr=30 lat=kwant.lattice.honeycomb(a=2.46,norbs=1) a,b=lat.sublattices ########### functions for structure build def rect(pos): x,y=pos return 0<=x