High magneto-Seebeck effect at room temperature in topological insulator Bi_2-xSb_xTe_3-_ySe_y crystal

We report thermoelectric and electrical transport properties of Bi_2-xSb_xTe_3-ySe_y by tuning y for a fixed x=0.2. In contrast to the reported p-type conductivity of the end compounds with y = 0 and 3, a dominant n-type conduction mechanism is observed for y = 1.5 from the Hall measurement. Intriguingly, the magneto-Seebeck consequence is enhanced up to ∼ 20 times for y = 1.5 compared to the end members which are well known topological insulators. The reasonable value of magnetoresistance with an anisotropic character with respect to the direction of the magnetic field is observed at low temperature, which decreases with increasing temperature. The density of state at the Fermi level near room temperature correlates high Seebeck coefficient as well as magneto-Seebeck effect. High magneto-Seebeck effect at room temperature is promising for the application.