Magneto-resistive property study of direct and indirect band gap thermoelectric Bi-Sb alloys

摘要

We report magneto-resistive properties of direct and indirect band gap Bismuth-Antimony (Bi-Sb) alloys. Band gap increases with magnetic field. Large positive magnetoresistance (MR) approaching to 400% is observed. Low field MR experiences quadratic growth and at high field it follows a nearly linear behavior without sign of saturation. Carrier mobility extracted from low field MR data depicts remarkable high value of around 5 m2V−1s−1. Correlation between MR and mobility is revealed. We demonstrate that the strong nearly linear MR at high field can be well understood by classical method, co-build by Parish and Littlewood, Nature 426, 162 (2003) and Phys. Rev. B 72, 094417 (2005).