Dilute isovalent sulfur doping simultaneously increases electrical conductivity and Seebeck coefficient in Bi2Te2Se nanoplates, and bulk pellets made from them. This unusual trend at high electron concentrations is underpinned by multifold increases in electron effective mass attributable to sulfur-induced band topology effects, providing a new way for accessing a high thermoelectric figure-of-merit in topological-insulator-based nanomaterials through doping.
Andras Kis, Guilherme Migliato Marega, Zhe Sun, Gabriele Pasquale