Effect of Chemical Potential on Thermoelectric Power of Bi₂Te₃ and Bi₂Se₃

Abstract

Temperature dependence of chemical potential was determined for n-type Bi₂Se₃ and p-type Bi₂Te₃ thermoelectric materials by means of angle resolved photoemission spectroscopy, and the determined chemical potential was compared with the measured thermoelectric power. We found that the temperature dependence of chemical potential is significantly large for the present materials and the large thermoelectric power is mainly caused by the chemical potential effect. This fact strongly indicates that the temperature dependence of chemical potential has to be properly understood to construct a guiding principle for developing new, practical thermoelectric materials.