Résumé
β-As2Te3 belongs to the family of the (Bi,Sb)2X3 (X = Se, Te) alloys, which represents a prominent class of thermoelectric materials. Thanks to peculiarities of their electronic band structure, these materials were recently classified as the first examples of 3D topological insulators, an exotic state of matter characterized by bulk band gap and gapless electronic surface-states. Taking Sn as a proof-of-principle, we demonstrate that the thermoelectric properties can be optimized by tuning the carrier concentration leading to a maximum ZT of 0.65 at 423 K. These results might also have several implications for the proposed topological state of β-As2Te3. Varying the Sn content enables achieving high bulk electrical resistivities at low temperatures, an essential requirement to unveil possible signatures of surface states in the electronic transport properties.