Galvanomagnetic and thermoelectric measurements on polycrystalline Bi88Sb12

Measurements of the electrical conductivity, Seebeck coefficient, Hall coefficient and magnetoresistance of Se-doped, Sn-doped and undoped Bi₈₈Sb₁₂ have been made over the temperature range 100 K to 300 K using transverse magnetic fields of up to 1 tesla. The material was polycrystalline and prepared by powder metallurgy. A simplified two-carrier theory is applied to the analysis of the experimental data and is shown to give a good qualitative description of the results. It is shown that the electrons and light holes have effective masses of the order of one-tenth of the free electron mass. On the other hand, the heavy holes have an effective mass in excess of the free electron mass