Valence Bands in Lead Telluride

Abstract

The magnetic field dependence of the Hall coefficient at 296° and 77°K, and the temperature dependence of the weak‐field Hall coefficient and the resistivity between 296° and 77°K were studied in single‐crystal samples of p‐type PbTe having carrier concentrations ranging from 4.9×10¹⁷ to 1.7×10¹⁹ per cm³. The Hall data at 77°K are quantitatively consistent with magnetoresistance data which have previously established the presence of 〈111〉 ellipsoids in the valence band. They are not consistent with a low‐temperature two‐band model, proposed by Stiles from de Haas‐van Alphen data at 4.2°K, unless the band edges lie at approximately the same energy (as Stiles found) and unless the carrier mobilities in the two bands are nearly alike. On the other hand, both the Hall and resistivity data above about 150°K do exhibit two‐carrier effects suggesting the presence of a lower mobility band at an energy about 0.1 ev below those bands which are occupied at low temperatures.