Enhancement in power factor due to anti-correlation between electrical conductivity and thermoelectric power and induced magnetic ordering in high mobility Zn doped Bi2Te3 topological insulator

Highlights: • Magnetotransport properties of Bi_2-xZn_xTe₃ Topological Insulators were studied. • Magnetoresistance shows the linear field dependence and with Zn content the MR value increases. • With higher Zn content mobility increases indicating increasing contribution of bulk in expense of surface state. • Interestingly, the electrical conductivity and thermopower increase simultaneously with Zn doping. • This simultaneous enhancement effectively enhances the thermoelectric power factor significantly. Electrical resistivity, thermoelectric power, magnetotransport and magnetization of Zn doped Bi₂Te₃ Topological Insulator were studied. Electrical conductivity is enhanced at higher Zn concentration, and the carrier mobility estimated from Hall data reaches a remarkable value of ∼7200 cm² V^-1S⁻¹. Large positive magnetoresistance (MR∼400%) is observed in high mobility samples. Interestingly it is found that the coupling between electrical conductivity and Seebeck coefficient is broken for higher Zn doped Bi₂Te₃ samples which effectively enhances the thermoelectric power factor (from 2.1mW/K²m for Bi₂Te₃ to 4.64mW/K²m for Zn doped Bi₂Te₃).