Transition-metal pentatellurides as potential low-temperature thermoelectric refrigeration materials

The importance of the future development of materials for use in low-temperature thermoelectric refrigeration devices is discussed. Specifically, results are presented on an interesting class of materials called pentatellurides, ${\mathrm{HfTe}}_5$ and ${\mathrm{ZrTe}}_5,$ which have shown promising low-temperature thermoelectric properties $(100\mathrm{}\mathrm{K}<T<\mathrm{}250\mathrm{}\mathrm{K}).\mathrm{}$ Substitutional doping occurs both on the metal site as ${\mathrm{Hf}}_{1-x}{\mathrm{Zr}}_x{\mathrm{Te}}_5$ solid solutions, and on the Te site with Se. Proper doping leads to a decrease in resistivity and an enhancement of thermopower which results in a doubling of the power factor (electronic properties) which is then very competitive with the power factor of existing thermoelectric materials in these temperature regimes.