“…From the relation ZT = α 2 σ T /( κ el + κ ph ), it follows that high thermoelectric performance is offered by materials combining high α and σ with low κ total . Intensive research effort is presently focused on new thermoelectric materials based on complex-structured compounds with low thermal conductivity [1,2], including AB 3 (A = Co, Ir, Rh; B = P, As, Sb) skutterudites, A 8 B 16 C 30 (A = Ba, Sr; B = Al, Ga; C = Si, Ge, Sn) clathrates, and mixed-cation chalcogenides (CsBi 4 Te 6 ) [2]. In this context, the tetradymite-like layered ternary compounds in the pseudobinary systems A IV B VI -( A IV = Ge, Sn, Pb; A V = Bi, Sb; B VI = Te) are also attractive, since these systems contain homologous series of n A IV B VI · m layered compounds, including a wide variety of mixed-layer compounds [3,4].…”