436
15 External Fields
Fig. 15.8 a Conductivity and b absolute value of the Hall coefficient versus inverse temperature for four p-doped (A–D)
and two n-doped (E, F) InSb samples. The doping levels are given in (a). Adapted from [1433]
Fig. 15.9 Carrier densities
in valence band (circles)
and impurity band
(triangles) from evaluating
the Hall effect on GaAs
doped with lithium (and
annealed) taking into
account two conduction
channels. Adapted
from [1434]
10
18
17
10
16
10
15
10
Hole concentration (cm )
-3
1000/T (1/K)
5
1 0
1 5
2 0
GaAs:Li
impurity band
valence band
100
Temperature (K)
50
200
70
(electron) distribution function f (E) is denoted as and is given as
3
=
ζ(e) f (E) dE
f (E) dE
.
(15.19)
In particular, the average
2 is now different from
2
. Considering the equation = =σ E for the
ensemble-averaged current density we find (for one type of carrier, cf. (15.12))
3 For this consideration it is assumed that the energy dependence is the decisive one. Generally, averaging may have to
be performed over other degrees of freedom as well, such as the spin or, in the case of anisotropic bands, the orbital
direction.