Electrical current flow

Comparing Eq. (5.34) with

$\vec{j} = σ \vec{E},$

(5.35)

we find

$σ = \frac{q^{2} τ n_{e}}{m^{*}};$

(5.36)

including the mobility

$μ_{e} : = \frac{q τ}{m^{*}},$

(5.37)

we finally get

$σ = q μ_{e} n_{e} .$

(5.38)

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