  Resistivity, Hall effect, Seebeck coefficient, thermal conductivity, heat
capacity, and magnetic susceptibility data are reported for CrSb2 single
crystals. In spite of some unusual features in electrical transport and Hall
measurements below 100 K, only one phase transition is found in the temperature
range from 2 to 750 K corresponding to long-range antiferromagnetic order below
T_N ~ 273 K. Many of the low temperature properties can be explained by the
thermal depopulation of carriers from the conduction band into a low mobility
band located approximately 16 meV below the conduction band edge, as deduced
from the Hall effect data. In analogy with what occurs in Ge, the low mobility
band is likely an impurity band. The Seebeck coefficient, S, is large and
negative for temperatures from 2 to 300 K ranging from ~ -70\muV/K at 300 K to
-4500\muV/K at 18 K. A large maximum in |S| at 18 K is likely due to phonon
drag with the abrupt drop in |S| below 18 K due to the thermal depopulation of
the high mobility conduction band. The large thermal conductivity between 10
and 20 K (~350 W/m/K) is consistent with this interpretation, as are detailed
calculations of the Seebeck coefficient made using the complete calculated
electronic structure. These data are compared to data reported for FeSb2, which
crystallizes in the same marcasite structure, and FeSi, another unusual
narrow-gap semiconductor.
