nextnano.NEGF - Software for
Quantum Transport

In this tutorial we present how can be calculated the generated carriers upon optical irradiation. The irradiation parameters are the poynting vector magnitude, Mid energy of the irradiation, Line width.

The transition rate per volume element can be expressed with the following sum: \[ R = R_{ab} - R_{ba} = \frac{2}{V} \sum_{k_a} \sum_{k_b} \frac{2 \pi}{ \hbar} |H_{ba}| ^2 \delta(E_b - E_a -\hbar \omega)(f_a-f_b) \]

In order to make evaluate the sum much faster we calculate the $H_{ba}$ matrix element at $k_a = 0; k_b = 0$(Remark: $k_a = k_b$), and we neglect the k dependence of it. Than we can simplify the sum in the following form:

\[ R = \]