Room-Temperature High-Performance Thermoelectric Bi0.6 Sb0.4 Te: Elimination of Detrimental Band Inversion in BiTe.

Room-temperature thermoelectric materials are the key to miniaturizing refrigeration equipment and have great scientific and social implications, yet their application is hindered by their extreme scarcity. BiTe exhibiting strong spin-orbit coupling peaks ZT at 600 K. Herein, we discover the synergy effect of Sb doping in BiTe that eliminates the detrimental band inversion and leads to an overlap of conduction band (CB) and valence band that significantly increases the S from 33 to 124 μV K-1 . In addition, this effect enhances the μ from 58 to 92 cm2  V-1  s-1 owing to the sharp increase in the CB slope along the Γ-A in the first Brillouin zone. Furthermore, Sb doping increases the anharmonicity, shortens the phonon lifetime and lowers κlat . Finally, Se/Sb codoping further optimizes the ZT to 0.6 at 300 K, suggesting that Bi0.6 Sb0.4 Te1-y Sey is a potential room-temperature TE material.