p-type PbTe is an outstanding high temperature thermoelectric material with zT of 2 at high temperatures due to its complex band structure which leads to high valley degeneracy.Lead-free SnTe has a similar electronic band structure,which suggests that it may also be a good thermoelectric material.However,stoichiometric SnTe is a strongly p-type semiconductor with a high carrier concentration,which corresponds to a minimum Seebeck coefficient and zT.