  High mobility phonon-glass semimetal $CuAgSe$ has shown promise in recent
years as a potential low-temperature thermoelectric material. It exhibits
reasonably strong thermoelectric performance as well as an extremely high
carrier mobility, both of which are enhanced when the material is doped with Ni
at the Cu sites. The exact mechanism by which these enhancements result;
however, is unclear. In order to further investigate the effects of chemical
substitution on the material's thermoelectric properties, we have prepared and
performed various measurements on $CuAgSe$ samples doped with Co and Cr
according to the following compositional formulas: $Cu_{1-x}Co_{x}AgSe$
$(x=0.02, 0.05, 0.10)$ and $Cu_{1-x}Cr_{x}AgSe$ $(x=0.02, 0.05)$. Measurements
of temperature and magnetic field dependent thermal conductivity, electrical
resistivity, and Seebeck coefficient will be discussed. Our results reveal a
remarkable sensitivity of $CuAgSe$'s thermoelectric properties to chemical
doping in general as well as a particular sensitivity to specific dopants. This
demonstrated tunability of $CuAgSe$'s various properties furthers the case that
high mobility phonon glass-semimetals are strong candidates for potential low
temperature thermoelectric applications.
