MULTIBAND CONDUCTION IN PB1-XYBXTE

Low and high field transport measurements have been performed on polyc rystalline Pb1-xYbxTe obtained by the Bridgman technique. Unannealed s amples show semi-insulating conduction at low temperatures while annea led samples remain conducting in the whole temperature range. The resu lts can be explained qualitatively by impurity levels lying within the fundamental gap. Using the magnetic field-dependent Hall technique, t he concentration and mobility of carriers in different bands (or sub-b ands) were extracted showing the coexistence of electrons and holes. T he attribution of discrete carriers to each band is discussed.