The GREEN's function matrices
are defined in the
basis set of ring numbers and subbands . Thus the diagonal elements
correspond to the spectrum of carrier occupation (3.79) of those basis sites
with a given energy . So the
total electron and hole density (per unit length) at a site is given
where the summation runs over all the subbands contributing to transport and
is the average distance between rings (4.3).
The factor in (4.50) and (4.51) is due to double spin
and double subband degeneracy (Section 2.4.2). To
evaluate these integrals numerically the energy grid should be selected such
that the numerical error of the calculation can be controlled. This issue is
discussed in Section 4.8.
M. Pourfath: Numerical Study of Quantum Transport in Carbon Nanotube-Based Transistors