Synergistic Performance of Thermoelectric and Mechanical in Nanotwinned High-Entropy Semiconductors AgMnGePbSbTe.

Introducing nanotwins in thermoelectric materials represents a promising approach to achieving such a synergistic combination of thermoelectric properties and mechanical properties. By increasing configurational entropy, a sharply reduced stacking fault energy in a new nanotwinned high-entropy semiconductor AgMnGePbSbTe is reached. Dense coherent nanotwin boundaries in this system provide an efficient phonon scattering barrier, leading to a high figure of merit ZT of ≈2.46 at 750 K and a high average ZT of ≈1.54 (300-823 K) with the presence of AgTe nanoprecipitate in the sample. More importantly, owing to the dislocation pinning caused by coherent nanotwin boundaries and the chemical short-range disorder caused by the high configurational entropy effect, AgMnGePbSbTe also exhibits robust mechanical properties, with flexural strength of 82 MPa and Vickers hardness of 210 H.