  We report calculations of the electronic structure, vibrational properties
and transport for the p-type semiconductors, SrAg$Ch$F ($Ch$=S, Se and Te). We
find soft phonons with low frequency optical branches intersecting the acoustic
modes below 50 $cm^{-1}$, indicative of a material with low thermal
conductivity. The bands at and near the valence band maxima are highly two
dimensional, which leads to high thermopowers even at high carrier
concentrations, which is a combination that suggests good thermoelectric
performance. These materials may be regarded as bulk realizations of
superlattice thermoelectrics.
