Electrical current flow

Comparing Eq. (5.34) with

\begin{equation*} \vec{j}= \sigma \vec{E} \qquad , \end{equation*}

(5.35)

we find

\begin{equation*} \sigma = \frac{q^2 \tau n_e}{m^*} \qquad ; \end{equation*}

(5.36)

including the mobility

\begin{equation*} \mu_e := \frac{q \tau}{m^*} \qquad , \end{equation*}

(5.37)

we finally get

\begin{equation*} \sigma = q \mu_e n_e \qquad . \end{equation*}

(5.38)

Additional information and several illustrative graphics can be found in the MaWi II script.