THERMOELECTRIC-POWER AND SCATTERING OF CARRIERS IN BI2-XSNXTE3 WITH LAYERED STRUCTURE

Thermoelectric power, electrical resistivity, and Hall effect of p-typ e Bi2-xSnxTe3 (0 less than or equal to x less than or equal to 0.030) single crystals have been measured in the temperature range 4.2 to 300 K. By doping Sn atoms into the host Bi2Te3 lattice, enhancements in t he thermopower and resistivity are observed in the intermediate temper ature range 30 to 150 K, and activation type behaviors are found in th e resistivity versus temperature curves with an activation energy of t he order of 10 meV which corresponds to the Sn-induced impurity band l ocated above the second lower valence band. For our experimental resul ts, we have also given a qualitative discussion about the scattering m echanism.