  The thermoelectric properties of PbSe have significantly improved in recent
years reaching figures of merit ZT 1.6. The transport properties of the hole
doped high temperature thermoelectric material PbSe are particularly
interesting and play a key role in this. Here they were analyzed over a wide
temperature and hole concentration ranges. The special features observed in the
variation of the experimental Seebeck coefficient, and Hall coefficient can be
accounted for within the framework of a two band model. Two valence bands
separated by a temperature dependent energy offset are considered. The extremum
of the light hole band has a density of states mass 0.27mo at room temperature.
It is non-parabolic and anisotropic and can be described by the Kane model. The
extremum of the heavy hole band is isotropic and parabolic with a much larger
density of states mass 2.5mo. We find that for heavily doped compositions the
high mass band contributes the Seebeck coefficient even at room temperature.
With rising temperature holes are transferred from the light hole to the heavy
hole branch giving rise to the anomalous temperature dependent Hall coefficient
which is found peaked near 650 K.
