The current flowing through the device can be computed from the converged Green’s function through the Landauer equation:(3)I=2eh∫−∞+∞T(E)f(E−EFS)−f(E−EFD)dE. here, h is Planck’s constant, f is the Fermi–Dirac occupation function, EFS and EFD are the Fermi energies of the source and drain, respectively, and the transmission coefficient T(E) is given by (4)T=−TraceΣS−ΣS†GΣD−ΣD†G†.