Synopsys: nanoribbon(n,L)

nanoribbon is the NanoTCAD ViDES class for the armchair nanoribbon. As inputs, it requires the chirality of the nanoribbon n, which corresponds to the number of atoms along the ring of the unzipped zig-zag (n,0) nanotube, and the length of the nanotube L expressed in nanometers.

The attributes of the classes are the following:
  • Nc (int) the number of rings along the nanotube
  • (int) the number of atoms along each ring of the unrolled (n,0) nanotube
  • Eupper (double) the upper energy limit for which the NEGF is computed in the nanoribbon
  • Elower (double) the lower energy limit for which the NEGF is computed in the nanoribbon
  • dE (double) the energy step computed when solving the NEGF
  • thop (double) the hopping parameter of the pz tight-binding Hamiltonian
  • eta (double) the infinitesimal imaginary part used in the NEGF formalism
  • mu1 (double) the Fermi level of the left reservoir
  • mu2 (double) the Fermi level of the right reservoir
  • Temp (double) the temperature of the nanoribbon
  • contact (string) can assume either the values “doped” or “Schottky”. If “doped”, semi-infinite nanoribbon are connected at both channel ends, repeating to the infinite the potential at the ends of the nanoribbon. If “Schottky”, Schottky contacts are taken into account. Advice: if doped contacts wants to be used, then it is advisable to exploit the nanoribbon_fast_ohmic class, which represents an improved version of the present class in terms of computational time.
  • E : (numpy array) array of the energies for which the transmission coefficient and the free charge is computed in the nanoribbon by means of the NEGF formalism
  • T : (numpy array) array of the transmission coefficient computed in correspondence of the energies stored in the E array
  • charge : (numpy array of length n*Nc) free charge computed in correspondence of each C atom of the nanoribbon.
  • x : (numpy array of length n*Nc) the x position of the i-th atom of the nanoribbon
  • (numpy array of length n*Nc) the y position of the i-th atom of the nanoribbon
  • z : (numpy array of length n*Nc) the z position of the i-th atom of the nanoribbon
  • atoms_coordinates : (function) it computes the atoms coordinates in correspondence of each C atoms, filling the x, y, z vectors of the nanoribbon class
  • L : (double) the effective length of the nanotube, which is the length of the nanoribbon composed by a integer number + 0.5 of unit cells, closest to the length specified by the user.
  • charge_T : (function) function which computes the free charge and the transmission coefficient in the energy interval specified by Eupper and Elower with an energy step equal to dE in correspondence of each C atoms of the nanoribbon. Such a computation is performed in the real space.
  • current : (function) it computes the current through the Landuer formula, once filled the T vector.
  • gap : (function) it computes the energy gap of the nanoribbon.
  • rank : (int) the rank of the process

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