Thermoelectric properties of two ternary tellurides

摘要

We present initial assessments of the thermoelectric properties of two ternary rellurides with known crystal structures, Tl_2GeTe)5 and Tl_2SnTe_5. Tl_2SnTe_5 appears to have a p-type figue of merit about the same as that of Bi_2Te_3, the best thermoelectric material among binary compounds. A good figure of merit is possible becasue the lattice thermal conductivity is very low. Based on neutron diffraction data, we have calculated atomic displacement parameters and thermal expansion coeffiencts. The atomic displacement parameters give s ome understanding of the low lattice thermal conductivity.