  The thermoelectric power S and the thermal conductivity k of stoichiometric
and vacancy-doped CaB6 have been measured between 5 and 300 K. The thermopower
of both materials is surprisingly large at room temperature. Across the whole
covered temperature range, S is negative and the temperature dependence is most
likely dictated by band-structure effects. The empirical interpretation of our
data involves a calculation of the thermoelectric power by using the Boltzmann
equation in the relaxation-time approximation and the assumption of a defect
band in the proximity of the lower edge of the conduction band. Good agreement
with our data is found by considering acoustic-phonon and ionized-impurity
scattering for the electrons in the conduction band which is well separated
from the valence band. The thermal conductivity k(T), predominantly due to
phonons, may also be described quite well across the whole covered temperature
regime on the basis of a Debye-type relaxation-time approximation and assuming
the concurring influence of boundary-, dislocation-, Rayleigh-, and
resonant-scattering on the mean free path of the phonons.
